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The iron tradeoff for software:
In oder to be viable, the people writing it need to make money.
In order to be viable, the people using it need to know that it won't go away when the creators stop making money.
Solve this, and you win.
Oh, and:
Build a tool that you need anyway for your dayjob, then Open Source it. (The Apache model.)
Plausible options I see are:
Charge for a premium version. (Docker is doing this now.)
Get sponsored by a patron that sells and ancillary service. (The Amazon model.)
Work a dayjob and build the thing at night. (Traditional open source.)