Can you rephrase that? I don't think I've read it correctly. It sounds like you are saying it would normally cost $50k on a 5090 and they can do equivalent work paying $1k. That's sounds like a $49k profit margin, but you say they will go broke.
Given their estimates of a Mac being able to generate $1k (per month?) a 5090 with a lot more power would be able to generate $50k. For a $3k piece of hardware. Which is obviously not realistic. (As in, nobody is paying that much for the images, which seems to match well with no actual requests on the system.)