Cross-gen is a gigantic hype killer, no doubt games will be negatively affected by that.
I heavily criticized Xbox at the beginning of the generation, and now I criticize Playstation, and I still point out as aggravating the whole "we believe in generations" marketing lie...
I understand the case of games that were already advanced in development and with an "easy Ps4/Ps5" adaptation... this adaptation period is acceptable, bad, but acceptable... Sony should have been transparent about this, like Xbox was! They sold a very different idea, an idea that the "new generation" would start right away, but that's not the case.
The idea sold was, "This is a new generation, let's make use of the new stuff, create impossible things for Ps4!"... and it became, "Our best games will be scaled between Ps4/PS5...". The only word here is disappointment, but sony has a good credit with me, they have the best games in the industry, the most critically acclaimed publisher of the last decade...sad but nothing "unforgivable", especially knowing they continue to deliver incredible games, notably more than the competition.

1)

Exactly. We're seeing that Spiderman is more or less acting as a major system seller for PS5 despite being cross-gen. The PS4 version dropped off the PSN chart in the US+ UK since January, the vast majority of people want the best version of the game, the one that was marketed to them and they'll wait til they get a PS5 to play it. Equally, most people are going to watch Horizon 2 and say they need a PS5 to play it on, not "I can't to play the downgraded version on my PS4". 

"... even if you removed the sales of the PS4 version this week, it would still have been No.1. The PS5 version accounted for 90% of the game's sales this week"

https://www.gamesindustry.biz/articles/2021-03-16-spider-man-miles-morales-scores-its-first-no-1-as-ps5-stock-levels-improve-uk-boxed-charts

The highest ratio the PS4 version has had was 30% during the games launch week when the PS5's userbase was literally none existent. 

2)

I'd imagine cross-gen development was decided a while ago based off assumptions on PS4's huge userbase and early estimations of the respective games release dates. People are still playing PS4 games in huge amounts but the above data goes against the idea that there will be a large audience for future PlayStation exclusives on PS4 in 2022. Although 10% of a 10m selling title, is still 1 million additional sales. I see Japan and Asia being the only exception to the rule where PS4 will get a healthier share of software.

I suspect also there is some freedom on the teams behalf too. Returnal and Ratchet have next-gen features which make them impossiple on PS4 (instant world travel in Ratchet and 60fps mandate+GPU driven bullet hell in Returnal). People may rub their eyes at the idea of Returnal not being possible on PS4 but there's a reason why its internal resolution is 1080p on the PS5. At the very least, the developers in question would have struggled to get it running on PS4 whilst maintaining their 60fps vision.

Horizon and GOW however are direct sequels that maybe build on top of last-gen foundations with high levels of fidelity being the focus instead of reinventing the wheel or having SSD driven mechanics. That may sound disappointing to some but the reality is diminishing returns means there's very little the last generation couldn't do in terms of traditional open world/3rd person gameplay. The negative impact of cross-gen in these games is more likely to be about the development schedule and extra time they need to port down versus restriction in game design. I dare say the Switch has my favourite open-world experience of the last generation in the form of BOTW, so I don't think power is a major limitation for inventive gameplay (more the creativity & ambition of the devs).  

Although the semiconductor shortage makes it extra unlikely, its still possible sony will discretely role out a final PS4 revision at a cheaper price. For example the gameboy micro was released after the Nintendo DS in most regions

Wha...whaaattttttt!? Who could've predicted this? Sony lying? Never!

This is good news for me. I don't plan on buying the PS5 until it's easily available and while the "squeezing through a tight passage" aren't very entertaining, they're just a mild annoyance to me so I don't feel like God Of War being cross-gen is going to impact it much.

I don't know how people can think this wasn't a PR stunt to generate hype. The games were announced for 2021 for that very purpose, knowing full well they would likely get delayed. Sure, COVID may have affected things. It affected everyone. But these consoles were released well into that, and they would know if it would push the game outside of 2021 or not by then. But what makes it even more shady, is that Sony announced these games with no mention of a PS4 version (except maybe Horizon?) right after saying, "we believe in generations". This was done for a reason. Now all of a sudden it drops that they are cross gen.

My problem is not the cross gen stuff, for Sony or MS. It is that Sony tried to go out of their way to hide it in order to drive hype. If we really want to turn this into a Sony vs MS thing like some people insist on, at least MS has been transparent and honest about it.

Now I know Sony and MS has games revealed early as well.  Look at Fable 4 and Metroid Prime 4.  But the major difference here is that niether of them promised a release year and both of them are constantly saying, "the game is still a ways out."  Sony is the only one who promised games a year later when it should be obvious they were not going to be able to deliver (COVID or otherwise), and then goes on to leave out cross gen while implying they wouldn't be, just to reveal half a year after launch that they are.

None of these companies are your friend, they all fk up in their own way.  In this instance, it is Sony.

"these consoles were released well into that [covid], and they would know of it would push the game outside of 2021 or not. "

If you've been following the industry for the last decade I'm not sure how you can make that statement. We've seen games get delayed 2months before release, there is never any certainty until the game is ready to go gold. If you're CD project Red then even that isn't a certainty. With only 6months of the year left, Sony still cannot confirm whether horizon will launch this year. So no, just because developers were already working with Covid restrictions back in summer 2020 it doesn't mean the teams automatically know exactly when their game is going to release in 2021. This is why the best practice is to just avoid hard release dates until things are a few months off.

They can definitely be more transparent in cases of knowing a game is cross-gen, but lets not conflate that with the developers lying with their initial release targets.

good, more close to BoTW, better.

climb, yes....

If you have been following the industry the past decade, you would know that when games get delayed that close to launch more often than not it is only a few months at most.  We were not even given a window of when GoW and GT7 might arrive, nor do we even know how far Horizon will be pushed back if it doesn't hit this year either.  If it is later than Q1 2022, it is obvious the game has been further off than what people were lead to believe (though I honestly believe this one is closer to being done).  In the case of GoW and GT7, it is without question the games were not even close to being ready for 2021, or we would at least have been given a quarter window at the time the delay was revealed.

Sony knows a lot more about what is going on within development of their games than you are giving them credit for.  But I suppose it would be easier to just take their word at face value and accept whatever they say to be the case.