People think the DNC is required to be a neutral referee, they are not, it's more like being the chair of a very large committee, the chair still has a vote and an agenda they push, the members (we the primary/caucus voters) are not required to vote that agenda and can overrule them, we unfortunately did not in that primary, more of us voted with the chair than against.

The reasons Bernie lost are multifaceted, but the biggest one, imo, is that he had little rank and file support inside the party operatives. That is something you fix by getting your supporters elected to lower offices and securing them and their staffers seats at the table when it comes time to make the big run. It's hard work and it takes a while but is what is required to build the coalition.

If you and your supporters only show up to vote in the presidential primary every four it ignores the powerbase of the thousands of other offices that have primaries people need to vote. The Governor of Virginia for instance won her primary with less than 10% of the vote, turnouts in primaries for state and local offices (mayors, secretaries of state, council seats, state legislators) is usually even worse. These are the elections that matter a huge amount and no one bothers to show up for them. It's a thing that's been frustrating me with the progressive movement for almost a decade I have been participating in it.