The N64 is fondly remembered because its best games haven't aged terribly. Games like Mario 64, Wave Race 64 and 1080 Snowboarding are still as good today as they were back then. If anything they are *better* today since making games of their ilk today isn't financially feasible.
You could bring up how GoldenEye 007 has "aged", but it's only in the combat and shooting mechanics. The actual level and game design hasn't aged terribly at all -- it's peerless as far as tiered-objective, stealth-based gameplay goes in an FPS, and again, because you can't make a shooter today with that sort of game design it's aged better than it should have.
GoldenEye has also aged in that from a modern perspective it looks awful visually. Even Mario 64 which is still praised today for its controls in 3D space still has the worst camera in any Mario game due to the time it was made. Don't really buy the argument that games become "better" because games like them aren't made anymore. Collect-a-thons are also not made anymore and I think those type of Rare games have also aged pretty poorly.
The N64 still has some of the most played games by speedrunners to this day. Nice try though
Of the reasons a speedrunner chooses to play a game, 'quality' is not necessarily one of them.