Revenue divided by time is a depressing metric for anyone who starts trying to monetize their hobby, but that’s not the point. Do your fun project because it’s fun. If you make enough to cash out on Steam, get yourselves some actual trophies. Or pizza. Trying to make money will force you to do all the depressing capitalist things the big studios do, and then it’s not fun anymore.
I used to pay a particular company by purchase order for this exact reason. CC takes 2-3% of the payment, but purchase order - they’ve got to get themselves into the company system, track the PO, invoice, track the payment…at the time, a common estimate was $50 to process a PO, and if you’re only buying $100 batches, that’s a big hit. Did not like that company, but they were the only place to get whatever it was I had to buy.