I would say similar to the startup world, it is going to be hit or miss (mostly miss). The potential is in being part of a small team (<10) that ships a game netting tens of millions of dollars in revenue. There are also a small handful of indie games with > $100M in revenue, those that get bought by Microsoft and Epic (i.e. Minecraft and Rocket League), and those that turn into the next Rockstar (they all had to start somewhere).

All that said, most don't go into indie games looking to strike it rich. They go into indie games because they are looking to make something unique and creative, away from the bureaucracy of the larger studios/publishers, with the potential for a nice "lifestyle" income.