This is a meta question.
The q2a core and most of the q2a plugins are open source. So earnings do not come diretly from there. Logically, there should be other sources of income.
Plus I assume, all developers working on q2a do it as a hobby, mostly.
With q2apro.com I have tried to bring some commercialization into live, to be able to spend more time on q2a and still have a living. However, total sales per month are max. around 100 USD. I don't know about other q2a developers, but I guess it should be similar low. (Correct me if I am wrong.)
So, open question out of interest, from what are you living?
- Is it a heritage of your rich father?
- Do you have a regular job besides?
- Are you a freelancer who lives from well-paying clients?
- Do you run another company?
In my case, I am having a big German mathematics project for schools which is quite popular: http://www.echteinfach.tv/ and helps me to pay my bills.
What about you?
PS: It would be great to hear that somebody is able to live from q2a. Because this would mean he could spend more time on the project and push it forward for the community...