Massive assumption. No indication that this developer wouldn't have used PSSR if they simply had more time.
The PS5 version is locked to 30 fps because the framerates don't get high enough to warrant an unlocked framerate.
They could have a performance mode that runs at 60 with a lower resolution, but again, you're talking about a smaller development team making this game on PS5, Xbox, and PC. It's a 40 dollar game and once again, when you're doing project management, especially as a smaller team, you can't always put all the bells in whistles in a game.
Every game? That's a bit of hyperbole.
I don't disagree that it is a nice to have though, because as I mentioned with Wukong it's going to sing on PS6, but so will all these games that eventually get PSSR and unlocked framerates.