Why no PS4 version? Power should not be a problem since it's also coming on switch
It's not about power at this point, probably.
There's just a diminishing interest in games for the audience of past-gen consoles after a certain point, and 2023 is late for a game of especially this indie type to be played by gamers who haven't upgraded. (It used to be that old game machines would be handed down from older kids to younger kids, but now young kids just game on their phones and don't need an old PS4 or Xbox One.) The value of the install base of a console seems an incredible draw because it's a big number, but many of those console owners have already bought their last games for that system. So you're starting to see some games now that are next-gen-exclusive (nee "current-gen") and some are "true next-gen" but some will stick out as seeming to not be doing anything next-gen in power, and that's one of the reasons why. It makes sense to focus on the platforms where the gamers are.
However, the 3D side of the world is rendered pretty well (it's a very natural global illumination use,) and it is maybe possible that it is using something like Lumen that doesn't work on PS4/One. Or Switch, for that matter. So it would have to be redone without that lighting system in the port. Porting that down to fallback traditional methods would be a pain in the butt, and wouldn't be worth it by the time this comes out for old PS or XB. But for the Switch market base, a game like could still sell very well, and so that version would be worth the effort. (Also, Switch gamers are used to their versions of games being distant cousins, whereas reviews and word-of-mouth would knock the game if it looked barebones on other consoles.) They can hire an external studio who specifically does Switch ports, have them do that, meanwhile they concentrate on the max version of the game, and hopefully all the versions they do ship turn out well enough.
Basically, this game is coming to Switch because it's the kind of game that
should come to Switch, so they're just going to make sure that happen, one way or another.
Very Nice. Reminded me of that Netflix show Hilda.
Funny, I must be a thousand years older than you, because it reminded me of this old Sesame Street segment: