[TallGuyShort]

Quite often the company's product is the open source project. It's just that instead of selling licenses, they're selling support contracts. You could get the software free, but for a fee you get to call the engineer that built it in the middle of the night for help keeping it running. And as a bonus, you get to leverage their ability to drive the roadmap when you have feature requests.

So really the debate here is not "do you hire an engineer full time or not?" it's "do you allow the output of that engineer to be open source or not?"

There's also a perk for the engineer: they work on stuff they can publicly point to as their portfolio full-time. Want to see me code? I don't necessarily have to have a bunch of side-projects on Github. Go check out the JIRA for these huge features I worked on!