It's not particularly constrained - human labor is cheap outside of the developed world. And propaganda is not something that you can scale up and keep reaping the benefits proportional to the investment - there is a saturation point, and one can reasonably argue that we have already reached it. So I don't think we're heading towards some kind of "fake news apocalypse" or something. Just a bunch of people who currently write this kind of content for a living will be out of their jobs.