In the article there is a link to this:
https://docs.google.com/spreadsheets/d/16mWB0J91JQJw0uhQZ1Kq...
https://docs.google.com/spreadsheets/d/16mWB0J91JQJw0uhQZ1Kq...
So a MVP that doesn't get a paying customer is not a success to me. Getting 1 or 2 paying customers, even $20, to me validates that people will pay for it. So far, he is 13.5k in the hole for no confirmed paying customers... so still seems an expensive experiment.