I guess it depends on what you call much. influence campaigns are clearly profitable, at least some of the time, but just because the profits are greater doesn't mean the costs aren't still significant.

And, I think the more active people are in countering propaganda, the more expensive it becomes to achieve the same effect. I think just believing the effects of propaganda are inevitable (and acting on that belief) has the effect of making deception that much more economical and effective for those who wish to deceive for their own selfish ends.