They're losing money now because they're making massive bets on future capacity needs. If those bets are wrong, they're going to be in very big trouble when demand levels off lower than expected. But that's not the same as demand being zero.
Stop this trope please. We (1) don't really know what their margins are and (2) because of the hard tie-in to GPU costs/maintenance we don't know (yet) what the useful life (and therefore associated OPEX) is of GPUs.
> If they stopped training and building out future capacity they would already be raking in cash.
That's like saying "if car companies stopped researching how to make their cars more efficient, safer, more reliable they'd be more profitable"