Progressives are a minority in their own party. We don't have the kind of leverage that you think we do. The ideas are popular, but I don't think even Dem party voters have the appetite to implement those ideas.
The actual reliable voters don't want to upset the current order. They are in their 40s, 50s and 60s. At different levels, they are established in their careers, they've paid off a good portion of their mortgage, have built wealth with retirement accounts and have have healthcare with employer or medicare.
Progressives need to start understanding the perspective of others in the party and not start labeling people sell outs or neo-liberals because they disagree on policy issues.