In the US, the politicians need money to be elected in the first place, and a lot of it. Lots of money comes from the big tech (to both parties), and the big tech won't give money to anyone with a plan to "rein them in."
They don't need money they just need votes.
If money can buy votes then the problem rests with an apathetic and distracted electorate.
You change that by giving a fuck and telling everyone you know what you actually think.
"Citizens United" might be the most ironic name in the history of western democracy.