It’s hard to compare memory bandwidth of these systems because of the various differences (e.g. different RAM types). I know that the theoretical RAM bandwidth for the N64 is way higher than what you can practically achieve under typical conditions.
At my last job, we had ASICs that allowed for single-sample audio latency with basic mixing/accumulation functions for pulling channels of audio off of a bus. It would have been tragically expensive to reproduce that in software, and the required hardware to support a pure software version of that would have been ridiculous.
We ended up launching a new platform with a different underlying architecture that made very different choices.