I think one aspect people aren't looking into as to why it's sales are half of the remake is that because the naming scheme is confusing. I'm not an OG fan of Final Fantasy, played only 15 and 16, but when rebirth came out I thought that it was like a remaster of the remake or maybe like a Pokemon variant like Sword or Shield. So consumers that aren't hardcore FF fans probably think that as well. But hey, I could be wrong and I'm probably the only one that thought of it like that.