Yes, unless you have a bitcointalk account with a high rank or have a team to do social campaigns in large numbers, it's hard to get bounty as your main source of income. I think with new people, it should only be considered a part time job.
Even those who have high rank account didn't able to earn much in bounties, especially if the project tends not to really pay their participants, it will still depend on the project if its worth investing and if it have what it takes to succeed over the period of time