Bounty campaign is almost becoming if not already a free service to project owners, because i do not understand why someone would work for months and paid almost nothing worth his effort. Some cannot even get a amount that is enough to buy a single meal from what they a paid. No wonder some people have left bounty and have started investing or trading, which is much better, because you might get your profit from that within a day.
You are spot on and it is difficult to put it any better than this. According to my estimates, less than 5% of all the bounties give the participants any significant rewards. The vast majority of them never pay, and many of those who make the payments do so in tokens which can't be immediately converted to BTC or ETH. Only a few noobs are doing bounties right now, as they don't care whether they receive the rewards or not.
The entire bounty system needs to be changed. At least a part (~ 20%) of the bounty reward needs to be paid in either BTC or ETH, to attract more bounty hunters. This pool represents just 0.2% to 0.5% of the total ICO funding and therefore it should not create any issues for the ICO promoters. But if they are refusing to do even this, then I guess there is no point in participating in such bounties.