Might take a while longer due to the cryptocurrency mining. Could make things prohibitively expensive

That's the only guarantee. I can promise you that they'll never make their console intentionally hard to dev for again unless they put a complete moron in charge like Xbox had at the beginning of this gen. 

The "hard to dev for" thing semi-worked with the PS2, but that was only because it had big momentum from the first PlayStation and full a year headstart on the Xbox and Gamecube. The Dreamcast was out but Sega had shot themselves in the foot so much from the previous gens that they couldn't continue to support it, so the PS2 was the only game in town for sometime before the other 2 even launched.

Sony thought that meant they could do whatever they wanted with the PS3, built foreign custom hardware in a time that PC style games were becoming more popular to reduce piracy and it backfired, big time. I read somewhere that the custom parts cost them 3-4 times what it would have cost with off the shelf parts with the same or even more power. The much-hyped Cell Processor was a disaster and it baffled PC devs with games either coming out butchered or in the case of Skyrim, outright broken.

Needless to say, I think they learned their lesson, and if I'm them, Mark Cerny would be the lead architect of every console they make until the end of time.

I don’t think It has anything to do with MS’s success (wasn’t it found that BC was barely used by XboxOne owners?). PS4 couldn’t have it because of the architecture change but the PS5 is expected to have BC.

What are you even talking about? It’s a difference if they offer a 4K upgrade of a console, or a slim version with a minor upclock for the same money, like MS have done with X1S. Sony have, from the start, done everything not to make the early buyers feel left behind. They simply wouldn’t allow a new slim model to make the old Pro model seem inferior.

No idea what your last comment even is supposed to mean in this context.

BC is used by XB1 owners. It may not be used to the point that it's a 'system seller', but for a lot of people it's a nice feature.

One way for Sony to get around the architectural issues with emulating PS3 games on newer hardware is to give the most popular PS3 games the remaster treatment. For publishers, it's a safe, but profitable investment. Since the PS5 is likely to be BC with PS4 games, it also means that it will be BC with PS3 games remastered for the PS4.

Uh... What?

Are you suggesting that there was no architecture change between the original Xbox and Xbox 360? Or there was no change between the Original Xbox and Xbox 360 to the Xbox One? Because you would be extremely incorrect.

Doesn't matter. Microsoft and Sony are competitors. Microsoft is using backwards compatibility to leverage themselves above Sony's offerings... And to an extent that has worked for Microsoft.
It also means that Microsoft is still able to sell old stuff, which collectors love.

I mean, so many Steam users have hundreds of games with like 37% of their library unplayed, Valve still makes a ton of money.
https://www.usgamer.net/articles/37-of-steam-games-go-unplayed-valve-titles-remain-most-popular

There is no difference.
Seems you are picking and choosing minor aspects when on the whole they are the same to assert your position.

Microsoft had to bring in the upclocks so that they could implement HDR, games running better was just a side effect.

Of course that was the reason...not that they wanted their early customers to feel the need to upgrade. Whatever suits your own agenda I guess.

I'm not picking minor differences...I'm mentioning a huge, fundamental difference. Especially since the Pro is an additional offer, not a replacement.

Both consoles (Xbox One S and Playstation 4 Pro) released after the Xbox One and Playstation 4.
Both consoles have increased power over their predecessors.
Both consoles as you put it "alienated" the prior user-bases.

If you cannot see and treat them as the same, then I am sorry. I disagree with whatever position you have.

Simple: If Sony would have stopped producing the PS4 after releasing the PS4 Pro you'd have a point. Disagree all you want then.

It's ridiculous to assume Sony would release an upgraded 5TF PS4 Pro Slim, which was the whole point of discussion. Has Sony EVER done something like that?

Depends, Sony could just opt in to remaster/remake games instead and it would have nearly the same effect but if customers really cared about BC they wouldn't buying PS4/Switch's in droves over an X1 since those systems don't offer BC with any of their predecessors ... 

It's the content we care about, not the functionality. Most of us don't care about BC itself, it's just a means to the access content we want and it's not the only one either ...