I have met some FAA flight instructors in the USA, over 2000h, licensed since 1990, and still flight instructor.(and good flight instructor).
this is a worldwide problem, and it is not only in aviation but in many sectors.there are 2 solutions for you: you give up and you take a stupid paid job which pay your rent and bills(with no real futur in the long term), or you do what you have to do to make it works(to do the job YOU want)...
I know many guys who would kill you to take your FI job.