Our company use lots of open source software. We don't pay for support. We have no idea where the creators get their money.
I think the only IT-related thing our company pays for is hosting, storage, backups... and we also use an open source fork of OpenERP which has a "foundation" behind it (maybe this will later become a company) and we pay the 2-3 main core devs money to travel to our office for discussion/bug fixes/client requests. I don't think we'd be paying them anything if we weren't asking them to actually physically come over here (from another country).
We don't pay for our operating systems, our database, our caching software, our full-text search engine, our server software, our webserver software/framework, or our development tools like editors, version control, testing (well, actually I think one dev here uses Eclipse, but even then I dunno if you pay for that or what). We get regular updates and bug fixes for all of this software. They are all popular-enough softwares that there is plenty of help info on forums, places like Stack Overflow, etc (as opposed to software so uncommon that nobody really uses it).
Surely this is where the impression comes from that open source software developers don't get paid... those holding that view are using the software and not paying. Most of our software isn't backed by a company (our server software for example became a real company just in 2011. It was started in 2004 by one dude)... a few are by foundations and communities, the rest are 1-3 people just making stuff and throwing it out on github or somewhere. Not difficult to see at all.
And it's because of this setup that tech companies come into existence and the IT industry is thriving. It's why/how our company exists, and our competitors, and some of our clients. Anyone can start something, so long as they have electricity, a computer, and an internet connection. And that's amazing.