The problem isn't individual members or efforts as much as it's the party as a whole. I think they have mostly coalesced around "Trump sucks," which he does, but I'm not sure what's underneath. It will take time to build, and I think people at a local level will try to build it, but I don't have any real faith in those up top. I'm wary of how much hasn't changed - there's still overemphasis on special elections that are very difficult to win (which means when Democrats inevitably lose, people are crushed and demoralized). There are still purity contests and proxy wars. People are still fighting shadow puppets over Bernie vs Hillary. Democrats in Congress are standing up to Trump, which is a lot better than where they were in W's first years in office, but I'm not sure how much is posturing and how serious it would be if he actually had a bargaining position they would work with.
Right now the whole party rests on Trump being loathed and feared. Once that is gone, the house of cards collapses.