How many of these sticks, powered hubs and controlling computers would you have to buy to equal one green 1U server? On the order of 64 USB sticks, 15 powered hubs AND one computer... That's 15 cheap bricks and a computer's power supply that have to be made and suck down power versus a quality, high-efficiency switching PSU that is about ~98% efficient. Doing the math on the supply chain sourcing of each component is pointless, because it wouldn't be practical, and at present, it's impossible to source all materials from goods to actual, verified origin (not shady middlemen).

Also, how much power would be lost by all those cheap bricks compared to a single, efficient switching power supply?

It also would be 65 systems to maintain.

Renting a fraction (via cloud/VPS) of a green server (good PUE DCs and LP gear) is far cheaper and greener. But more importantly, waste fewer computing resources.