The greatest career move a politician can make is to take an issue that lots of people are suffering from and make sure it is never solved but people still think they are the one who can solve it. This is Bernie's whole career (among others).
Bernie is one of the few politicians that have a voting record which aligns with their rhetoric, going back decades.
Bernie never won the presidency though?
I don't dislike Bernie, I'm pointing out a trend among politicians.
Maybe don't use him as the archetypal example if he's not even an example of it. He seems to do well for his constituents. The problem is that people outside his state keep (stupidly) choosing not to be his constituents.
Being president pretty much ends your power/influence. So if you don't get what you want accomplished, you're not getting it done. As a Senator, you get 6 years every time you win an election. With that, some people are more effective not being president.