Atlus doing Atlus things.
So Persona 3 FES came out soon after Persona 3 with new content, then Persona 3 Portable came out for the PSP without FES content but included a new protagonist option. They then released Persona 3 Portable on Steam earlier this year.
And now when they finally have the chance to combine both content they decide to cut BOTH of them. Crazy.
I hope the remake will at least have some new content of its own to make up for it...