Generation is all screwed up because of the Wii U. That thing only lasted for 4 years so Switch was released in the middle of 8th generation

I always lump a generation in terms of their hardware capabilities... Each generation tends to introduce a set of technologies that are applicable to all hardware.

I.E. 9th generation is about rudimentary ray tracing.
8th generation was all about Tessellation.
7th generation was all about programmable pixel shaders.
6th generation was all about hardware Tranform and Lighting. (TnL)

And so on.

That would mean the WiiU and Switch 1.0 were 8th gen and Switch 2.0 is 9th gen.
Also means that the Gamecube and Wii are 6th gen.

I called the Switch Gen 9 just to trigger people. You know, because PS4 and Xbox One were old news. It was fun. I will continue with the Switch 2. It's Gen 10, PS5 and Xbox Series are last gen now, lol. =P

After reviewing the evidence and some heavy thought (way more than this topic deserves) I'd say it is indeed 10th gen and Switch started the 9th gen. They brought HD Rumble which was the first sign of haptics even though it is not really haptics but a cheap imitation, it may be a weaker system but that's not changed categorization before but mainly for one fact, and this was difficult to see back in 2017 cause it was inverted but now Switch has spent more time with the other two in 9th gen than the other two in 8th gen and unless something catastrophic happens (The ps5 is set for '27 and I'm sure they are eager to get new hardware out there in masse with PSSR built in after the mess that is this gen and FSR, now realising most people want 60fps at graphical loss).

That's over simplifying things. 7th gen could be said to be all about motion controls and 9th gen all about the SSD, speed and ease of use as more defining characteristics. 

Except the Wii, WiiU technically had "SSD's" aka. Solid State Storage and not Mechanical Storage. - So did the PS1, PS2, N64 and more, albeit, their solids state storage was removable.

The Xbox 360 also had variants that included a 512MB/256MB/4GB Solid State Storage Drive.

There have been more consoles with solid state storage in one form or another than with consoles that had writable mechanical storage.

Motion controls existed previously. - Sega "Hang On" Arcade Cabinet, PS2 Eyetoy, Sega Activator, Nintendo Power Glove, Essential Reality P5 Glove and more.

I am talking purely on hardware feature sets obviously... As Consoles or more specifically the GPU companies that consoles use, tend to rely on PC hardware development and R&D in terms of graphics technologies as they follow certain standards.

I haven't heard for a long time that someone puts Gamecube and Wii in the same generation...

Most people say that the definition of gen 7 is motion control.

Well if this generation is marked by Raytracing then it has failed at that. The difference is barely noticable for such a drastic hit to frame rates. Even on the PS5 PRO it isn't really all that great compared to PC's with 4090s that can really make use of it enough to be a noticable improvement.

I'd say 9th generation is more about upcaling tech if you're just counting hardware features and probably 10th gen will also be about AI but in a more general way and less specific to one problems solutions. There will be DLSS on Switch 2 and Sony now has PSSR, Xbox have... ugh, idk.

God knows what AI will be handling come PS6 and Xbox 5. Maybe they'll be able to dynamically alter the difficulty to provide the player with exactly whatever challenge they desire right the way through the game making difficulty options actually reflective of their names and not just a slider that makes things more spongey or your health is reduced. Perhaps NPC AI will become dynamic as well and learn in real time with the player making Solo MP games with bots have an experience like real MP. Development times may reduce drastically as AI takes on the heavy load of rendering details well enough that an artist can come in and polish them up and add soul qnd TLC instead of spending weeks on the interior of cars in games like GTranturismo, it could be two or three days to get the whole thing done and devs will be back to getting games out in two or three years like back in PS1. 

Yes, it's the early onset of the 10th generation. It's just a way to lump systems together that exist together for the most amount of time, if we are being honest.

I am speaking from a technology perspective of course.

And remember, the Gamecube was originally designed/demonstrated to have Wii's motion controls first.
https://www.thegamer.com/prototype-wiimote-gamecube/

I would imagine the 6th console generation would have played out very differently if the Gamecube came with that instead.

Hence "Rudimentary" Ray Tracing.

Consoles have had Ray Tracing for a long time in one form or another.

6th console generation games like Conker and Shrek used a single light bounce, Xbox 360 and Playstation 3 had subsurface scattering, Xbox One and Playstation 4 used real-time global illumination in some games.

The 9th gen is the generation where it started to become hardware accelerated, which is the key differentiator.

Upscaling has been around for awhile, consoles aren't really hardware accelerating it yet, other than the PS5 and the PS4 pro.