Trump's pivotal point was Super Tuesday where the Republican moderate vote was split between 8 choices: he was able to build an insurmountable lead.

Much like marijuana legislation finally passing now, i think it will take the previous generation to die off before we start seeing more democratic progressive candidates like AOC. Bernie's numbers were Yuge and dominating with people under 40. Give it another decade or so: if gen Z shares values with gen X and Millenials, which is yet to be seen, i think the AOC type candidates will make inroads in many places in the Democratic party.