I mean i enjoyed palworld quite a lot. Id consider it a good game. Generally player counts come from either enjoyable gameplay or brain manipulation tactics like dailies/FOMO - palworld doesnt really have the latter from what I see. It checks lots of boxes for enjoyable gameplay - rpg elements, open world with exploration. meaningful collection, creativity options via base building, and some level of tactics/strategy in teambuilding and combat.
The incredible map with deep oceans and rewarding exploration are what made it popular. I cant think of another game that makes you WANT to be in the water. Hard to replicate that, but turning the ocean into a puddle and making half the game land-based certainly didnt help.