I don't think it's pay that's the issue. I'm sure you can survive perfectly well on a politician's salary. Some of us make little or nothing anyway, because we don't want to play the corporate games. The issue is that rational people who value established facts will have difficulty getting elected when running against people who rely on manipulating emotions and telling people what they want to hear.

Edit: also some parts of the world, like the US and UK, have district-based voting systems that favour large parties. You can't actually get anywhere in politics without the backing of such a party, and it would be difficult to convince the party to make you a candidate when you aren't playing the same political games.