The problem is not that the politicians can be bought but that enough economic power is political power and today it is mainly carried out through the financing, and therefore the control, of the mass media. Not only news but also movies, books, TV series, shows and so on.
And when I say political I don’t mean only parties, elections etc. For example medical research being privately funded will only develop profitable products, such as drugs that chronicize a disease and the development of those that cure permanently are discouraged.
Same with other scientific fields like the economic one, funding the absurd doctrines like the NeoClassical one while burying Keynes.
Not to mention cultural impoverishment, the promotion of ideologies such as social Darwinism, individualism, materialism, nihilism, positivism, scientism: all functional to the preservation of power and the control of the masses.
This was extensively discussed in Marx’s Das Kapital and even the two thousand years old Bible has monitions on this.
In particular, separation of powers principle has its roots in Plato and was discussed by Locke and Montesquieu.
But to the legislature, executive, a judiciary powers you need to add at least the informative (already known as the fourth power), the economic and the technological ones.
@post
So you basically agree with me. The problem isnt the money, its the fact that politicians can be bought
@rbreich