I'd really like to work for Mozilla on Mozilla products, but somehow the interview process is broken.

I've managed to go through 3 interviews (2 technical, one with the team-coordinator) but then was rejected because they've found some other with more years of relevant (?) experience on the topic for the position.

Now they write this. So my question is: why don't you open more positions, letting people be hired (and paid) to work on products, instead of looking for charitable work from volunteers?