Bitcoin Developers , getting paid ?

[OmegaStarScream]

I was really wondering , why people help to develop Bitcoin ? is it their main job ? If it's the case then how they are getting paid and from who exactly ?
I assume that creators of Lightweight wallets gets only donations and money of advertising for Trezor or other hardwallets as-well .

[pedrog]

Why people write open source software?

Enjoy.

Also this: http://www.gnu.org/gnu/manifesto.html.en

Stallman is like the father of open source movement.

[DimensionZ]

I remember Mike Hearn saying that he has left his previous job to work full-time into Bitcoin development so I guess they receive royalties or direct payment from the Foundation. Also if you can get sponsors you can pretty much get by just from that.

[OmegaStarScream]

Ty for both links , I also found on a post (can't find the link) that Bitcoin core developers get like 100k per year ? who could confirm that