I thought about something similar in a previous post [0]. What if you ran a service that floated a large number of accounts and circulated logins for a larger number of users? At the moment it looks like sharing accounts is legal [1] but I'm sure the services would clamp down on it they thought it costs them money.
0. https://news.ycombinator.com/item?id=20732231
1. https://www.androidauthority.com/netflix-account-sharing-100...