I don't see your point. If you want money go make money, it's not unattainable and it's fairly easy to get if you have skills. If any of those developers really wanted to prioritize money I'm sure they'd have no problem making plenty of it.

If you want to make free open source software then do that.

If you want both then build a business model around your open source software.

Without context that's not a very useful set of numbers! Did they select themselves out of better paying jobs or were they discriminated against?

Those people are basically telling him to give up on opensource and get a "real job".