To be fair you would be a very high volume customer to be spending 60g and I think you would get a reduced unit price.
I have some 300w Tt heatpipe fanless PSU's that would be prefect for this and they don't need a motherboard, cpu, RAM so you are saving money there. They could also be used to help keep alternate blockchains ticking over and for people in countries with high electricity costs. I will be looking into ordering one soon.

You can the  also consider that the rate of inflation in fiat money is only getting faster and that few lousy grand you dropped on some FPGAs is nothing will be quickly forgotten and you will break even before you know it.