As far as electing someone as president, sure it makes them less relevant. It just seems strange to me that someone like Sanders can run for office, but have such a different political position than the vast majority of the party he is running with. The very fact that he doesn't call himself a Democrat should speak volumes.
If Bernie had never branded himself as a socialist, and focused on one or two impactful new potential government programs (such as healthcare reform/single payer), he would be winning the Democratic ticket by a landslide. Instead, he praised Cuba, denounced capitalism, and pushed a lot of agendas that most moderate democrats were not on board with (cancelling student loans, free college, green new deal, housing for all, moratorium on deportations, universal childcare, etc.)
The country has been slowly turning left for a long time. Democratic Socialists have nothing to do with it. The Woke Left and Socialism are scaring a lot of people in the other direction.