It's really the same in any creative industry. Employers exploit you through this combination of factors:

1. You love the area and are willing to take a cut to work in that area, particularly when the alternative is working on CRMs for a PBM;

2. Demand for these jobs still exceeds supply; and

3. The very top of this pyramid makes a shitload of money. If you get to like a Lead Engineer type position, you might be making points on unit sales. And for a big hit that can be big money; and

4. Historically, indie development wasn't a viable route to making a living but it suffers from the same distortions too. For every Notch or ConcernedApe, there are thousands of pepole who below the poverty line. Look at something as widely regarded (but niche) like Dwarf Fortress. They made bank (and deserved it) from the Steam release but they spent 10+ years making a couple of thousand of dollars a month between the two of them.

Just look at the music industry. There are artists and bands who are trying to make it, training for years and making $50 to play some local venue and they're just hoping to get noticed. In years gone by that was a record contract. Nowadays, there are alternate routes. Justin Bieber was a Youtube breakout.

Fun fact: the first artist to have a #1 single without a record contract was Lisa Loeb for Stay in the early 1990s because it was picked up for the sound track (those used to be a big deal) for Reality Bites.