> but if it didn't work in general, we wouldn't see so much money pouring into political advertisements.

We might, because professional political strategists (who advise campaigns on what works) tend also to be involved in the firms that do this work, and direct their clients to spend money with entities in which they have a financial interest. It is an industry which is absolutely rife with the kinds of conflicts of interest that wouldn't be tolerated for long elsewhere.

And its also an industry where people very often fail upward due to connections rather than succeeding on their track record.