Right, but to pass any bills people we have to actually take power. This is especially difficult when you turn your nose at communities which have historically been important blocs of the Democratic coalition.
Lofty goals don't over-promise, but instead set the agenda for years or decades to come. One of the Democrats' biggest problems is their allergy to hope ideology. Every policy proposal should be connected into a consistent and positive vision of the future. Obama didn't do this per se, but instead inspired many voters through his vague promise of change. By offering no long-term goals and laughably suggesting that "America is already great", Hillary did basically the opposite of this. Technocratic reforms are boring and bad for electability, especially when they primarily benefit a wealthy few.
So your solution to people preferring to buy snake oil is to sell more snake oil?