Here in bitcointalk, that's the only stable way to earn, specially if you are enrolled on a good campaign that pays high.. But not all of it will last forever, I could even see some campaigns that lasts not even longer than one month.. So if you want to have a stable income, try other things around and invest money into bitcoin and use it to earn more..
I am part of my campaign since last 2 years and I am successfully earning bitcoins since then and I have never faced any issue with my payments but yes there are not many campaigns that will last for long time.