There's actually a lot of money in HTML5 games right now. I posted a detailed rundown of my earnings from games on reddit a while ago: http://www.reddit.com/r/gamedev/comments/xc4rs/anonymous_ind...

These are all fairly simple games. Nothing fancy.

My main job is still maintaining and selling my game engine ( http://impactjs.com/ ) - where I can't complain about money either.

s/HTML5/Flash, a decade and a bit ago. The market for them will mature, but at the moment not many people are making much money from it, since it's new tech.