Former Square President Hisashi Suzuki once let "Father of Final Fantasy" Hironobu Sakaguchi run wild and make a terribly-expensive bomb of a movie called "Final Fantasy: The Spirits Within". It lost a ton of money, and could have almost killed Square. Sony apparently felt kind of responsible, having encouraged Sakaguchi to do it, so Suzuki arranged for Sony to bail out Square by buying 18% of Square.
That patched things up, but Square's shareholders were still upset, so they basically fired Suzuki and Sakaguchi (in spite of them putting Square on the map) and put Yoichi Wada in Suzuki's place, and Wada quickly merged Square with Enix, and then proceeded to pretty much ruin both companies for many years (Suzuki laughed on Twitter when Wada's SquareEnix crossed the threshold of being in a worse position than Square by itself was when Suzuki got fired). The merger with Enix also had the effect of severely reducing Sony's ownership of SquareEnix. Although Sony never owned a controlling share of anything, they were just an important major shareholder, and still were after the merger, so... *shrug*
SquareEnix then proceeded to make Final Fantasy games on the GameBoy Advance, and Final Fantasy 13 on the Xbox 360, Dragon Quest 9 on the DS, Dragon Quest 10 on the Wii U... and this is after the PSX Final Fantasy games were ported to PC, where they've been hanging around almost forever.
Sony recently sold their share in SquareEnix.
This reporter is apparently theorizing that the sale of Sony's shares broke some sort of contract that was locking Final Fantasies 7, 8, and 9 (just those three) to Sony consoles (except PC, because reasons), and that those three games could've appeared on Wii U but didn't because Wii U, and that's it's not a matter of SquareEnix simply not caring to port those three games around until now. Well actually, the Wii U part was SquareEnix not caring, but everything else (umm, GameCube and Wii?) was contracts.