There's also the part of "authorial intent" where particularly at that time many of the games were designed and developed sometimes on much bigger hardware (corporate mainframes, for instance) targeting the consoles and then later QAed on development consoles (that might not even be the same hardware as production consoles). There certainly are questions for some games if the authors intended something much better that they could get their development hardware to perform. It's not that many console hardware generations back where even development consoles still varied in hardware from production consoles (at least as recently as the early history of the PS3/Xbox 360).

All told, it's all a part of game's version of the "the artwork is never quite finished/realized, it's just eventually published".