I've wondered about the possibilities of closed ecosystems paradoxically making it easier to open source your software and still make a profit.

There's still risk to your bottom line by open-sourcing: a competitor could use your code/ideas to create products that outsell yours. But what you don't have to worry about is piracy: the number of users with jailbroken devices or a dev certificate are a small subset of your user base.

On the positive side, you get the benefit of customer engagement: people helping you bug-fix, creating level editors, community content, etc. Companies can also sometimes find and hire top-tier talent this way.

At any rate, major kudos to Insurgent for doing this. I'm actually a little disappointed that all their games are free; I think at the very least, they should pick their best game and charge 99c, or do split Lite/Full versions.