You’re not the first to discover vintage tube gear… People have been aware of the merits of vintage gear for a long time. Look up Western Electric gear from the 30’s, then you’ll realize what people are willing to pay for vintage tube gear/speakers.
Restoring a vintage tube amp requires more than some new tubes and a couple of coupling caps. And not all vintage gear is worth restoring. The gear that is, will demand higher prices.
There is no free lunch. You want to play, you have to pay.