It really depends on certain things. First your rank can determine how much you would earn. There are higher stakes assigned to higher level ranks, and also the amount that is put up as the bounty reward, which will be later divided depending to the number of persons that participated, and what's not. This are the factors that affect how much one can earn from bounties.

not as much as you can make when you actually investing

There are several sections in a bounty campaign. People can make big money by doing signature and translation! In some bounty campaigns, Article, Content has the highest value. In Amazix managed bounty campaigns, a good content creator can earn more than 15 ETH from one bounty campaign! Now, you will know why bounty is a good opportunity to make money, Though day by day social rewards is decreasing because of the huge participants