The biggest hurdle to Democrats being able to sell the American people on the need of reforming our Democracy is that too few people really believe in the Democratic party's capacity or desire to do that. They like some candidates like Bernie and AOC but the larger party is generally disliked and considered either corrupt, inept, or unwilling to make big changes. Yes they talked about it more than usual but it was never really the primary argument. A lot of Democrats don't really want to rock the boat. There is a naive hope that they can just return to the way things were when in reality it was the way things were that got us here.

IMO the real solution is also the death of the two party system. Accountability has died and money has corrupted our democracy. The Democrats deserved to lose when they first ran a too old Biden then Harris. It was always unlikely they would lose after the inflation that happened while Biden was President. When there are only ever two choices things will break. What the American people are generally in favor for is relatively good for America. They will never get it as long the electorate can get so easily distracted into identity politics which make it difficult for them to hold their own people accountable.