if ifs and buts were candy and nuts
All of the above is a complete hypothetical, there is zero evidence that consoles are going anywhere soon and I don't know were you got this consoles are declining from, PlayStation revenues are way up (record breaking for them), Nintendo just beat loads of records with Switch, PS5 is in line to be as successful as PS4 (maybe more so), the only complete failure is MS, and yet, according to you , they are in the best position, or at least better than Sony. And as far as 1 game per year, so far that is true, but that doesn't mean it will stay like that (missteps with GAAS has slowed down development for a good few PlayStation studios), and even with 1 game a year, quality over quantity each and every time for me.
I think you have it in your mind that because MS is going the PC route that everyone will buy that instead of consoles? consoles (by comparison) are cheap, that's the main reason why they sell, one less console, one that has been floundering for a while, isn't going to change that, in fact, due to MS's exit (if that happens) I expect PlayStation to do even better.