There’s a couple factors, but to oversimplify, games are just very complicated. If you had a high-end recording studio, you might have a high-end computer (for the time) to digitize recorded audio. You just need to basically record a microphone and be able to play it back, so its not too complicated anyway. In the same vein, for animation and CGI, a studio would have super high-end computers, and even then it would often take days for the computer to process a single high-quality image or much longer for animation.

Compare that to games, where you need to generate an image in about one 30th of a second. At the same time, the game has to also play back sound, handle a bunch of extra input and logic for the game, and has to do it all on a computer that an average family can afford.