Today's game music is technically of a higher quality and complexity. But it's nowhere near as interesting, and I dare say, not 1/10th as good. Yesterday's game composers had to possess a certain ingenuity, working, as they did, under tight constraints.
Creativity can flourish under a constricting framework, often in ways it fails to do in the absence of limits. This is why $200 million Michael Bay movies often suck, while a movie made for a fraction of the price can kick ass. Bay doesn't have to be creative. Nothing presses him toward ingenuity. That's not to say that today's game composers aren't good, or that I necessarily compare them to Michael Bay. Rather, it's to say that the composers in the '90s had to be good. They had to go out of their way to be good. They had to achieve so much with so little.