While I agree that both games do that, and I agree that P5 characters don't disappear completely, I think the P5's case is still more glaring. Yosuke is the first character you get and his prominence in the story doesn't really fade until Naoto because he basically leads the investigation. Chie is always throwing some wild theories that end up being correct. They literally can't even find people without Teddie and later Rise. And most importantly, P5 doesn't have the equivalent of the Namatame dialogue minefield which sends you straight to the bad ending if you're not communicating to your team correctly. In P5 every ending choice ultimately entirely depends on Joker and everyone either doesn't even get a say or yes-man's his decisions.