You have a really strange understanding of the word "parity". And why did you upgrade if it was parity?

I am not an expert on the subject but visuals/effects does appear to have have a fairly significant impact CPU. For example, games aiming for 60 fps solely on X1X tend to leave graphics settings lower due to their impact on CPU.

Gears 5 on PC says world textures settings has a significant impact on CPU. Therefore it makes sense Gears 5 on X1X didn't boost texture quality for that reason, in spite of having more RAM.

Games can be developed with the superior 9th gen CPU in mind, but I suppose the engine needs to be designed to scale back CPU needs as well for certain visuals, reduce physics fidelity, etc. Stuff like this has been fairly common in PC games for decades.

So if people have the impression CPU is solely frames and AI instructions, that isn't the whole story. There are plenty of CPU usage aspects that can scale back without breaking the experience, but reducing 60 fps to 30 fps is an easy start for cross gen content.

I did because I game on a 65 inch Oled and the boost in resolution was worth it for me. But playing the same games, just a bit better isn't enough reason for  everyone. That's why relatively few people upgraded to a mid-gen console.

I'm also no expert but this is an interesting read about the Switch port of Metro Redux and why the cpu was a pretty big hurdle and not so much the gpu. https://www.eurogamer.net/articles/digitalfoundry-2020-metro-redux-the-making-of-an-impossible-port

If A is better than B, there is no parity! Parity means the quality or state of being equal or equivalent: https://www.merriam-webster.com/dictionary/parity

If the enhanced resolution was it worth for you, the visuals aren't equal and there ain't parity.

4K instead of 2K resolution ain't parity.

60 fps instead of 30 fps ain't parity.

Solid 30 fps instead of wonky 30 fps with slowdowns ain't parity.

Solid 60 fps instead of wonky 60 fps with slowdowns ain't parity.

High-resolution textures instead of low-resolution textures ain't parity.

To keep it short:

Also if 4 times the resolution is only "just a bit better" in your opinion, it could have to do with the fact that you are sitting 13 feet away from the TV. People who sit nearer of course can see much more details; for them the difference will be bigger. https://gamrconnect.vgchartz.com/post.php?id=9110183

A lot of "if" for a relatively short period of cross gen titles.

Content and features parity may have been important for X1 and X1X, but we don't know if that includes cross gen.

Visual and performance (60 fps and sometimes higher) aspects will be a big drain on CPU resources. These upgrades are part of next gen and that can scale back.

SSD being utilized is really just games streaming data more quickly (textures for example) and faster loading. These are things we see PC games do already while having standard HDD support. These are aspects where RAM and CPU also help.

Why would X1 ports have to look and play like a different game? Scaling back games isn't building something entirely new, it's tweaking games to run well on inferior specs. Whether that's significant changes to visuals to reduce load on GPU/CPU/RAM/storage, reducing NPC/enemy count, cutting performance, etc.

The Witcher 3 for example seemingly tweaked many aspects to function well on Switch. Yet it surprisingly still supports cross save with the PC version in spite of all of that.

I don't think anybody has suggested simply reducing resolution and frame rate is always enough. There is also reducing visual aspects that have load on CPU. Some gameplay related aspects can be tweaked without breaking the game, like physics or NPC/enemy counts. Hence, a lot of tweaks can be done to make games work better on lesser specs. Crysis 1 on consoles can be seen as a notable example.

When Crysis 3 or BF4 were being designed they were working higher end PCs in mind and the vastly inferior 7th gen consoles at the same time. The end result was fairly impressive 7th gen games and tech showcases on PC were released at the same time.

Hence, I would be a little concerned if MS was building games on X1 only, then porting them to Series X. To the contrary, it seems they build games that can function on X1 but are also much more impressive on superior specs. Gears 5 and Forza Horizon 3/4 have been examples of this in a pre-Series X world.

That 4x CPU power can be utilized for 60 fps (or higher) more often, increased visual fidelity in aspects that have CPU load, faster loading, more NPCs, better physics, maybe more split screen experiences, etc. Hence, these are aspects we expect to improve in the 9th gen, but can also be scaled back on 8th gen versions.

More CPU power doesen't change how games are fundamentally designed. Every game isn't suddenly going to become a tech demo. Certainly not in the near future where many projects are still cross gen.

I know what parity means. I said games that are designed with parity in mind, meaning they are designed so you get the same core game and visuals on all platforms and a +++ version on platforms with higher-end hardware. A game can be 8k and 120 fps on high-end pc but the core game would still be designed to run identical on the jaguar cpu of the ps4/Xone. 

Did Gears 5 have better physics, ai, world simulations, more npc's and biggers multplayer maps with a higher player count on pc and X1X? There are some exceptions like Shadow of Mordor, BF3 and Forza Horizon 2, but it's pretty rare to see a cross gen game that has core features missing from the pc version. MAybe they are doing that with MS's exclusives and Halo Infinite will look like a half ass version on X1. But it's far more likely that the core game will be identical on X1 and Series X but upscaled to 4k and a higher fps.

It will still look great obviously, and I'm sure it will be a good game. However if you look at something like GTA6 that will likely skip current gen. I'm pretty damn sure it will not be just a 4k/60 fps version of GTA5. It will be a dramatic leap over GTA5 in terms of map size, physics, world simulations etc. and it will probably have drops below 30fps and run at 1440 or 1080p on next gen consoles.

And yes, cross gen games do tend to be pretty much the same across gens in the first couple of years. That's why the 1st party exclusives are important, as they're usually the only games that showcase what these consoles can do early on. 

CPU tasks are scalable as well, just as scalable as graphics tasks.

Many rendering techniques are very CPU-heavy like reflections and shadowing, even some forms of Anti-Aliasing is done on the CPU as is allot of post-process filters.
A.I. can be scalable in the amount of actors you have on screen. - Physics can be scaled upwards or downwards in precision and thus CPU loads as well.

Battlefield on PC dual vs quad core CPU.
If you loaded Battlefield on a PC with a dual-core processor, the game would recognize that and reduce the amount of A.I characters in the game. I.E. No barking dog behind a fence.

Price isn't an issue for me. I spend upwards of $2,000 on phones every year or two. I own a high-end PC. $600 is a small price to pay for the best console hardware.

In saying that... We don't know what the price is, it hasn't been announced. The Xbox One got burned partially by price as did the Playstation 3, lessons were learned.
Microsoft did get it's userbase adjusted to a $499 price point with the Xbox One X though.

That's actually false.
The PC has been scaling games across multiple generations of CPU's for years now.

You can take a game and run it at 30fps on a Core 2 processor and scale it up to the latest Ryzen 8-core chips.

Framerates are the responsibility of every component in a system, not just the CPU.
If you are GPU bound, you will be framerate limited.

The texturing settings in Gears 5 having a CPU impact is likely due to texture decompression being handled by the CPU cores.

The flipside is that a game like the Witcher is likely being held back by the GPU on the Switch.

Every game is different, every game has different hardware demands.

You start leveraging some of the instructions that Zen 2 is proficient at (Like AVX) and Zen 2 will be probably closer to 8x faster, possibly even more... I.E. There were instances where Zen 2 was 150% or more faster than Zen 1 in some AVX workloads... At the same clocks. - And Zen 1 was a big step up over Jaguar, not just in AVX, but also clockrates!

AVX deals with Vector extensions, which is very important for things like Physics calculations, which is why Physics in the 8th gen were a big step up over the 7th gen.

Resolution is always important. Up to a point.

PC's are obviously different. PC isn't constrained by memory.
The average mid-range gaming PC today generally has 16GB+ of System memory and 8GB+ of GPU memory, that's 24GB total. - The OS isn't likely to push past 3-4GB for itself and can reduce it's footprint down to 1-1.5GB if push came to shove.

The Xbox One and Playstation 4 have roughly only 5GB - 5.5GB of Ram, Xbox One X. - 9GB.

There is simply less of a need to stream data into memory on a per-needs basis on the PC, so the requirement for an SSD is significantly lessened.