This reward you get for any bounty depends on the allocation and the number of participants. there are some campaigns like social media campaigns where you have so many participants working to get a few percentage of the bounty reward. So you wont expect the reward for this to be as much as article or video with a fewer participants and bigger allocation.
That's true! The reward depends on the allocation of the campaigns. Furthermore, it's true that doing article and video campaigns can bring you more tokens than doing social campaigns. The reason is that not a lot of people dedicate their work to do article or video campaigns because it takes a lot of time. That's just a common thing, easy job, lower payment and we all know that!