Bug bounties are an option, but there are plenty other options. I.e.: do not charge indie devs or small companies until they reach a certain amount of revenue,

Bug bounties are an option, but there are plenty other options. I.e.: do not charge indie devs or small companies until they reach a certain amount of revenue, and make the code available to anyone paying or not - that's what FOSS is about IMO. If there is something that really benefits the world out there, then indeed it can be unlicensed.