Ok.. here's the thing.

1. There is no reason for MS to not have the XSX support the XB1 controller. Why? because outside some slight ergonomic changes, both the XSX controller and the XB1 controller ae identical. The same can not be said about the PS5 DS controller. If you feel the changes that the controller brings is major or not, going to be used or not, is irrelevant.
   
   The bottom line s that there are things that the controller can do that the DS4 can't do, and if sony wants to push devs to support those features, they have to make it the only option for PS5 games. If they don't do that, third party devs would just ignore the features. Which would mean sony would be inadvertently shooting themselves in the foot by having games on their platform support gameplay mechanics that simple are nowhere else on the industry. 
   
   Lastly, this a business, money is made from selling controllers. That's partly how console hardware subsidization is justified. And sony wouldn't just be looking to sell controllers to PS5 gamers, but also to PC gamers when those PS5 centric gameplay mechanics enabled by the DS starts being supported on the PC too.
2. And now that crossplay example you gave... Its just the way it is. The simple fact of the matter is that it's a bad tool for business for a platform that is the market leader, and its a good tool for one that isn't. 
   
   Remember back on the PS3/360, whenPSN was still free. Sony was pushing for crossplay. MS refused. Now the PSN is the market leader as with paid online gaming and user base, and you can't see why MS would b pushing fo it now and sony would be refusing?
   
   These companies are competing, who do you think it favors when your friends don't have to buy the console you have to play online games with you? MS is trying to take away the single biggest thing that makes people buy consoles only second to games; word of mouth. Friends buy what their friends have, with cross-play, they wouldn't have to. 
   
   We can call it anti-consumer all we want, but by that reasoning, every single timed or permanent exclusive is anti-consumer too. But these are all tacts used to give a platform more value. Now you can disregard everything just said if MSdoesn't have a single timed exclusive game on their roster.
   
   Honestly, though, I think that the fact MS turned down crossplay back in the 360 gen should have told you everything you need to know about it. Do you really believe that if the tables were turned MS would be pushing for crossplay as they are today? Its like people forget that MS at one point paid for exclusive GTA4 DLC. And a Tomb Raider timed exclusive. 

Ok.. here's the thing.

1. There is no reason for MS to not have the XSX support the XB1 controller. Why? because outside some slight ergonomic changes, both the XSX controller and the XB1 controller ae identical. The same can not be said about the PS5 DS controller. If you feel the changes that the controller brings is major or not, going to be used or not, is irrelevant.
   
   The bottom line s that there are things that the controller can do that the DS4 can't do, and if sony wants to push devs to support those features, they have to make it the only option for PS5 games. If they don't do that, third party devs would just ignore the features. Which would mean sony would be inadvertently shooting themselves in the foot by having games on their platform support gameplay mechanics that simple are nowhere else on the industry. 
   
   Lastly, this a business, money is made from selling controllers. That's partly how console hardware subsidization is justified. And sony wouldn't just be looking to sell controllers to PS5 gamers, but also to PC gamers when those PS5 centric gameplay mechanics enabled by the DS starts being supported on the PC too.
2. And now that crossplay example you gave... Its just the way it is. The simple fact of the matter is that it's a bad tool for business for a platform that is the market leader, and its a good tool for one that isn't. 
   
   Remember back on the PS3/360, whenPSN was still free. Sony was pushing for crossplay. MS refused. Now the PSN is the market leader as with paid online gaming and user base, and you can't see why MS would b pushing fo it now and sony would be refusing?
   
   These companies are competing, who do you think it favors when your friends don't have to buy the console you have to play online games with you? MS is trying to take away the single biggest thing that makes people buy consoles only second to games; word of mouth. Friends buy what their friends have, with cross-play, they wouldn't have to. 
   
   We can call it anti-consumer all we want, but by that reasoning, every single timed or permanent exclusive is anti-consumer too. But these are all tacts used to give a platform more value. Now you can disregard everything just said if MSdoesn't have a single timed exclusive game on their roster.
   
   Honestly, though, I think that the fact MS turned down crossplay back in the 360 gen should have told you everything you need to know about it. Do you really believe that if the tables were turned MS would be pushing for crossplay as they are today? Its like people forget that MS at one point paid for exclusive GTA4 DLC. And a Tomb Raider timed exclusive. 

Every PS5 owner will have the new controller. So they can test those new features with the new controller. But games like Minecraft and overcooked that is known for its local multiplayer most likely wont use those new features. And that is where the using your old controller comes in and allows you to save money. Is it really hard to support practices like this? Why does allowing the consumer to save money on controllers have to be so complicated? Microsoft is also a business. They are wasting potential $$$ so it can benefit the players. 

And why do people have to keep mentioning the past. Both companies clearly have changed since then. And this is why competition is good. Its good for MS to keep up with Sony. We cant just let 1 company set all the rules.