The Apollo Guidance Computer ran at roughly 40 kHz with 4 KB of RAM. It got us to the Moon because the maths was solvable on paper — Newtonian, two-body, slide-rule territory. Three days, three astronauts, a known orbit.
The blockers between us and the asteroid belt aren't mechanical. They're mathematical: N-body trajectory optimisation across decades, autonomous proximity operations on rotating irregular bodies, spectral inversion against unknown mineral mixes. None of that fits on a slide rule.
One next-generation training cluster now does more arithmetic per second than every computer on Earth combined did in 2010. That is the actual story.