Don't be so sure. Take for example steemSTEM community. They were paying 50 $ to a single post easily, but on stateofdapps they have 10 likes. Imagine that 150-450 rewarded users per week - 10 likes

Or the recent case of Utopian and Indiegogo, about 20.000 $ distributed per month, but in the campaign... They asked for 35.000 and after 2 months they've got 5.000.