It doesn't matter how much compute you have, you'll always be able to saturate it one way or another with ai and having more compute will forever be an advantage.
If breakthrough in ai happens you'll get multiplied benefits, not loss.
That depends on how fine-grained the matrix multiplication is (and if that's actually the core workload). Past a certain scale you can't get away with brute force (and Moore's law doesn't fix that insofar as orders of magnitude of difference will exist no matter where you are in that progression, allowing for qualitatively different capabilities between better algorithms and worse) examining every parameter every time, which could push the world to something where the branchy nature of CPUs and their better amenability to true random-access memory makes them win out.
