SpaceX has put a ton of excess capacity on the market that was subsequently absorbed by Anthropic. There's a reason why Grok is no longer free.

Meta said it was considering doing the same because they saw how valuable excess capacity was.

You're misinterpreting what actually happened.

SpaceX is selling compute to a willing buyer. You can't point to one side of the trade as evidence for under/over capacity. The way we usually judge such things is the price. If the price for compute is going up, which it is, then that's the thing to look at.