Bernie is okay, though. I'm sure you hear less about all US candidates in general during midterms, especially when the average congressional district is unlikely to have one running every other election.
Bernie does it the right way. Build a base of support to influence people who will then influence the politicians.
Most politicians are going to make platforms based on polling numbers and a general sense about what the voters want. Kinda how things are supposed to work in a representative democracy. The politicians are supposed to represent the people when passing laws and setting policy.
As nice as it sounds in theory to be able to check a box beside the name of a person that agrees with you already, it's just not feasible because everyone has different ideas and different priorities. So you gotta check a box beside the person that's most likely to be sympathetic to your ideas and priorities (and actually has a shot of actually being a representative) and then make some noise to convince them they should do something about the issues you care about.
I didn't really catch the distinction between what Bernie does and what any other politician is doing. In both cases you check a box for who you think represents you the most. Bernie just has to try a little harder to stay on the ballot.
The hard part is getting people to run for office, getting funding for the campaign, organizing events and groups and managing staff to accomplish the goal of getting on the ballot and even then having a chance of winning is a bit of a long shot.
And worst of all, if you're less moderate than the adjacent party then you're going to split the vote of that party's constituents and lead to the opponent's party winning.