And they wont be foolish to pay for
non-results for long...
It's far from obvious to me that you could tell apart the effects of different efforts - especially as you don't know who each voter voted for.
Companies that do those short of campaigns stagger them at different times, do polls before and after, test a new method in this or that area or demographic and check again and so on through election year.
It's not just "apply a bunch of methods at once" -> "check the final election result" as the only feedback.