I think you should at least talk to people who have a broader range of views about the causes of mass surveillance. I've worked on fighting it for a while and I've come across a lot of different theories about why it exists and persists. A few of them include

* international anarchy theory: the world is really dangerous (much more dangerous than the public has any idea of) and so security agencies need to be more powerful than people, including the security agencies themselves, would really prefer in order to combat that danger or keep it at bay; surveillance is one part of the security agencies' toolkit for managing it

* international hegemony theory: the U.S. got its current position in the world partly via unsavory means and means that are very poorly understood or poorly remembered by the public (at least in America) (cf. Huntington's "The West won the world not by the superiority of its ideas or values or religion [...] but rather by its superiority in applying organized violence. Westerners often forget this fact; non-Westerners never do.") and there is some reason for the U.S.'s sake, U.S. allies' sake, or the world's sake that the U.S. should continue to maintain this position, including by continuing to use the tools that allow it to do so

* realpolitik theory: the U.S. in some sense can't afford to be that much more ethical than other actors because they will somehow take advantage of this

* military-industrial complex theory: surveillance is super-profitable for surveillance vendors and contractors, so they want to keep it going

* self-perpetuating elites theories: civil servants are accustomed to seeing surveillance activities that they participate in, or whose intelligence products they consume, as part of the way the world works, and they normalize it among themselves while just not caring very much what anyone else thinks about it

* non-political theory: currently the ideological anti-surveillance constituency is so tiny that most legislators find it rational to ignore it, as contrasted with other issues that generate multiples or orders of magnitude more passion, contributions, or votes

* public support theory: public opinion actually favors current surveillance programs, at least in broad outlines

* class conflict theory: someone, or some coalition, is relying on surveillance in order to keep suppressing the lower classes

* racial conflict theory: someone, or some coalition, is relying on surveillance in order to keep suppressing racial minorities

* other conflict theory: some other kind of powerful coalition finds surveillance important in order to maintain its power

* surveillance is actually good theory: sophisticated legislators and other officials have taken a look at the laws and institutions that carry out surveillance in the U.S. today and concluded that they are basically OK under the constitution, are basically subject to half-decent oversight, and represent a broadly politically acceptable trade-off in terms of what they accomplish and the risks they create

I think approximately two to five of these are well-aligned with your view that campaign finance reform would be relevant to achieving surveillance reform, but the others aren't so well-aligned. Although I have my own opinions, I don't feel like I know for sure which of these theories are most correct.