While many of Musk's endeavors have huge claims/visions behind them, it seems to me that the people behind them are actually good at testing them in a smaller scale and relatively quickly getting to a point where they are generating money, instead of staying up in the ivory tower.

Take the Boring Company which after a couple of prototypes landed actual contracts. Working momentum is powerful, even if it takes several times as long as people hope it would from the onset.

Who knows, maybe they'll even end up with a hyperloop in twenty years.