That's sort of how digital music streaming works...for consumers mostly and not so much for creators. I mean even if I put $100/month into something like Flattr, across the thousands of open source authors whose work I use, each would get about a penny.
The consumer just pushes money into his account (maybe 5$ monthly) and lets the system distribute it monthly.
The distribution is influenced by visiting flattr-enabled websites, staring projects on Github, etc.
However, this is a donation system. There is no obligation for the receiver, while Percival envisions it as payment for maintenance.