On BDSP, Legends was supposed to be that. They thought it was too different, suddenly switch direction and changed a bunch of resources, and threw the Gen 4 remake to some random company that did a shit job (and for some ungodly reason was invited on to help with Gen 9) - There's even assets including a 1 to 1 remake of the players room from DPPt in Legend's code

That said, yeah the lack of time given by TPCi is only part of the problem. The people running GameFreak, for some ungodly reason, refuse to use the money and resources they have to hire more people. They intentionally keep one of if not THE smallest AAA team in the industry

Apparently, TPCi is having internal talks about how they don't give GameFreak enough time, though, and apparently are also getting pissed at GameFreak's higher ups refusing to hire more people, so HOPEFULLY this leads somewhere, but yeah

There's a reason why even with ten or hell, a hundred years, I still doubt GameFreak could produce something. Time fixes half the problem. Their refusal to hire people however means they could be given all the time in the world and still not be able to produce because most of the time would be spent updating to new tech when they could double or triple their team size and have people actually dedicated to that part