Palworld is an early access and unfinished game. Logically, they are not going to squeeze you out day one when they still lack extra content to sell you if they also already charge you for that early access.
You have a lot of faith if you believe that a game with that basic nature (MP survival cooperative) and the need to expand to avoid falling into interest will maintain support solely by maintaining the purchase price in its early access state.
Microtransactions, or expansions, or DLCs, etc. are going to be a fact for the game at some point, as happens in 90% of the cases in this type of proposals. Especially in those super successful ones.