Sadly this is actually an improvement for Atlus. Could have been Persona 3 Reloaded: Royale with Cheese re-release at full price.
Yeah... their behavior sucks in general. They were remaking this game for some time now, all that content could be in remake from day one so they are full of shit cutting in something that was in P3 releases for years.
I get that Persona 5 got Royal version after they made all this new content, in this case FES version was there for over a decade.
But this is their standard behavior, I bought persona 5 on (big) sale, while I was completing it persona 5 royal released. I didn't give a shit and completed vanilla version. After few years I bought royal on another sale but didn't touch it in PS4 pro. When ps5 port released THEY OBVIOUSLY didn't get players any option to upgrade (I'm not even talking "for free" hahaha) or even transfer saves. I'm now playing PS4 pro version of royal on ps5 but of course I would prefer native version. I'm not giving them any cent now, I will complete P3 on game pass trial bought for cheap on eneba.