Maybe that's true on a sufficiently large scale, but for local/state politics I don't think it applies. For example, I would imagine that several policies in San Francisco and the Bay Area would be very different if political influence was perfectly correlated with wealth/capital.
On the other hand, policies of e.g., local government in North Carolina reflect the influence of the pork industry really clearly.
If unlimited campaign spending is so advantageous to the political insiders, and entrenched interests, then why are they (McCain, Feingold, and other long-term career politicians) so opposed to it? How often do you see a politician advocate for something that puts them at a significant disadvantage, and helps their critics?
Long time incumbents can assume their position is safe unless there is a well funded challenger. Incumbents have plenty of air time and name recognition.
>"Long time incumbents can assume their position is safe unless there is a well funded challenger."
You have restated my position quite succinctly; FEC campaign regulations are a way of preventing "well funded challenger[s]".
Right. Money is not the only source of power.
Absolutely not! Money is one of the most obvious forms of power in society, and therefore any group that has a lot of money to spend, is, by definition, already a significant part of the power structure. "Outside groups" with money are never true outside groups.