Contractors in London with React (which I don't do), can make 600 EUR/day. That's well over $8k/month.

It's a great scheme, and I applaud them for it, and it's a hike up if you're non-Senior, but for about 10%-20% of engineers I know it's a pay cut for 3 months. That's OK, you get to work on something awesome. Not bad, really.

I'm a contractor and if someone offered me $8K per month for a 3 month contract building open source software of my choice, I would leap at it with both hands. Normally I do the same thing, but I don't actually get paid. ;-)

I suppose I should be spending more time looking out for this kind of thing. It's possible there is more money in open source development than I had previously considered.

That's also less than what a contractor on say 10000 EUR/day would make.