President Trump won because against incredible rigging and hostility from 'pubs, he prevailed and took the nomination away from the uniparty puppetmasters. Could it be Trump won because fed up voters were even more fed up when Hillary was given debate questions for a debate against Sanders? It might be that if the DNC had a system where the voters actually chose the nominee, they might've won.
Biden could have won. The problem with Webb or Sanders was that you'd probably get a third party candidate in the race -- a liberal or progressive against Webb, a moderate or Establishment candidate against Sanders -- and that would have complicated the election enormously.