For a policy to be achieved, say like the $15 minimum wage it must either have very broad support or have some sort of compromise where by people who don't support the policy will vote for it in exchange for support for a policy they do support.

Surely you understand that many Democrats are not progressives and almost none of the Republicans are progressive. Passing any progressive policy almost requires a miracle. If you want to pass progressive policies, work in jurisdictions where progressives are in a majority.