And yet you cite a paper in which Footnote 1 is a long list of articles that do find such links. I'd quote it, but it's quite long and those interested can read it for themselves. Point is, "one study found X" =/= "generally agreed by scholars that X is true."
Second, the study doesn't actually examine whether PAC contributions affect votes - PACs aren't necessarily ideological but the paper only evaluates ideological voting patterns. It looks at, for example, Am. Conser. Union (ACU) scores and finds that politicians' overall scores don't change much if at all on average in their last term. So, the paper finds that ideological conservatives vote conservative in their final term. It doesn't find that "PAC contributions from the for profit college industry had no effect on votes on higher education loan subsidies." The papers in Footnote 1 do look at PAC contributions ===> PAC votes and find the expected correlation.
Third, taken at face value, the study indicates big money identifies candidates friendly to their interests on the front end. So Wall Street backs candidates with a history of supporting Wall Street, and their huge war chest helps them get elected and reelected. That the Wall Street friendly candidates vote that way even in their last term doesn't mean the money from Wall Street had no effect.
Finally, I don't think the PACs and other big donors are stupid - they know the money they spend has an effect.
Here is one passage:
I'm not sure what the importance is of those distinctions. And it's not an either/or question - almost surely it's both. PACs influence votes and PAC money helps elect members friendly to that PAC's interests.
Well, I did read the whole study, briefly, but I suppose you'll claim vindication because I didn't accept that the findings prove what you think they proved. If you care about what is true and correct, maybe you'll have some response to the points I raised.