The hell it is.
The only reason the example is older is because that was the last time they were in a position of strength (at least in USA). Make no mistake: Microsoft would never promote crossplay if they were still on top. They are historically one of the most anticompetitive corporations in the software industry, and have been sued etc many times for abuses of their dominant market position. All this is directly applicable to the current topic; it is simply in their DNA.
1. I've never seen evidence that Sony was in favor of crossplay with Xbox in the PS3 days, just that they would do PC crossplay (which matches their current opinion on crossplay)
2. Treating a giant company like a singular person and acting like complete changes in leadership can't or won't change how a company operates, is quite a foolish opinion
3. If in the future Xbox decides they don't want crossplay anymore, guess what, people will start hating on Xbox for doing that, so who cares about a hypothetical situation in the future. It's like you're trying to justify a pro-company anti-consumer move just because your favorite company is the one doing it, instead of caring about what is OBJECTIVELY a pro consumer move with no possible negative effects for you as a consumer, so why are you so against it?
Also this notion that Xbox players are desperately in need of crossplay because of low player counts is hilariously misguided and nothing but fanboy-driven nonsense, crossplay allows friends to play with each other, and allows dying games to last longer (or even thrive) on every platform, the ONLY potential downside to crossplay is PC crossplay (which Sony has no problem with btw), in terms of keyboard+mouse and potentially more hackers, but even that gets overexaggerated.
I hope every single company does this and makes it very clear that Sony is the reason for no crossplay, so Sony is forced to stop with their nonsense policy that hurts the industry just because they're worried that people might game more on other platforms if they aren't held hostage by Sony. And I promise you that I wanted crossplay just as much in the 360 era, just in case you try and argue that I only want crossplay because Xbox is "losing".
Newsflash, it's possible to be in favor of a decision Xbox makes and against a decision Playstation makes, and STILL BE A PLAYSTATION GAMER, I swear some people here seem to base their opinions on a decision based solely on which company made it (and yes Xbox fanboys are just as bad, but this is a heavily Sony slanted forum so the Playstation fanboys are more prevalent here)