The PS5 has struggled just to scrape past ~60-65 million units after four years on the market. Sony knows the PS5 will never catch up the PS4 at this point and they know they will be totally fucked once the Switch 2 is out and GTA 6 isn't going to save them. Sure they will probably get a big boost in sales around the game's launch but it won't do much to save that sinking ship.
The PS6 will very likely be the last Sony console at this point, and depending on whether or not Sony decides to make it portable will determine if they will even be able to survive in this industry, but even if they do make a portable console what would be the point? Almost all the Sony "exclusives" are on PC now and we all know it won't be long until they start bringing everything over to PC day one. Most people will look at the next console and ask why should they bother when they could buy a Switch 2 or a Steam Deck.