World GDP is ~100T per year. I'm guessing that estimate was just the amount of rare earth metals times the current price, but the magnitude it ignored economic realities is comedic.
16 Psyche is 2.3e19 kg, according to WP, so 10 quintillion dollars works out to 43¢ per kg. It's pretty plausible that any kind of metal would be worth at least 43¢ per kg, it wouldn't even have to be very rare. Even steel is worth abut that much. If you're going to use it on Earth you'd be better off mining iron ore on Earth, but you can't do that with platinum-group metals, and if you want to use steel for construction in space, it's a huge advantage if it's already there instead of having to be lifted out of a gravity well.
I don't think there's an obviously correct way to compare economic value across generations' worth of time. 100 years ago people didn't have antibiotics, so death from infected wounds was common, even wounds that would be minor today. But old-growth lumber was abundant.
It might take decades, even centuries to return that to Earth, and of course how would they be able to do that, the amount of fuel required itself would mean that the price of that would be huge.
I doubt solar sails would be that viable, and the idea of the oceans going dry in order to produce the fuel to return metals would be a tad far fetched.