"The complexity and depth of Nintendo 64 games suffered as a result".

Hmmm. I'm not so sure that N64 games did suffer in that way as a result of cartridges. Sure, there wasn't as much third party support as Nintendo hoped (understatement!) but a lot of the games that did get produced certainly didn't lack complexity or depth. For example, Ocarina of Time is full of depth, Goldeneye certainly didn't lack detail. There's plenty third party games that have sufficient complexity/depth as well; Shadow Man, Quake 2, Duke Nukem Zero Hour, Turok 2, etc, etc...