> Corporate executives frequently go in to politics, and when politicians retire they often get cushy, high paying jobs

This can explained by some benign reasons: both political and management jobs require similar skillsets, like leadership, charisma, speaking publicly and so on. So it makes sense that same people could do both. Furthermore, if a political position involves regulating a certain industry, a person taking it has to have expertise in that industry, which further makes it more approachable for people from the industry.