I already have a powerful PC, but I also have a PS5 for some occasional first party (Demon's Souls mainly, and Ghost of Tsushima, Nioh 1&2 or Bloodborne before on PS4) and mostly for its third party exclusive like FFXVI (was very hyped...), Returnal. Can't say I've been very impressed by what I've played so far. Returnal was good but FFXVI lacks what makes a great RPG.
I eagerly await Rise of the Ronin on PS5. This one justifies (like FFXVI and Demon's Souls before) the existence of a PS5 in my living room (with 4K blu-rays).
FFVII Rebirth I can wait for the PC port (still haven't played the Remake), and I might wait for the whole trilogy to come out in a definitive edition on PS6 or PC. Same for Stellar Blade. Not incredibly hyped by them but I appreciate the effort, and those will be for sure really good games. But I can wait.
There's also games like Granblue, Helldivers 2, Silent Hill 2 that I might buy, but on PC (and I will likely double dip for Rise of the Ronin).
To resume, PS5 is a must for some very occasional games that I can't wait to play. So if they go full PC with their games (first and third), I will for sure ditch the console. It pains me to see the state of release of Rise of the Ronin, as it will get a much cleaner look with better shadows and framerate on PC, like the Nioh series.