They're in precisely the same position the Republicans were in before Trump: they're the only viable and not completely-detestable party for about half the vote

They're in precisely the same position the Republicans were in before Trump: they're the only viable and not completely-detestable party for about half the voters, but are doing a really bad job of working on what those voters want. Republican Party leadership in 2015-2016 wanted more of business as usual, and to keep power. Trump came in talking just like an actual Republican voter in a midwestern diner, with the credibility of being a party outsider, which cut the legs out from under them because they have sucked at representing their actual voters for decades. This struck such a grievous blow that he quickly took over the entire party. Then he either actually did things Republicans had been selling voters on for years but not delivering (Roe v Wade, gone, thanks to his Supreme Court), or at least kind-of ineptly tried to do things Republican voters have long wanted but Republican politicians never really even tried to do (the stupid wall, tariff China, destroy [well, uh, replace with a barely-different agreement, but whatever, names matter] NAFTA). It took him bumbling his way through a pandemic to lose, and not by that much, he'd almost certainly have gotten a second term if not for sheer chance despite all the blatant corruption and daily incredibly stupid bullshit, that is how effective this strategy was. Democrats won't improve and will struggle to win elections until something similar happens to their party. This will need to include abandoning strident neoliberal economic policy, as it did for the Republicans, because voters never liked that and it only worked because both parties stuck to it regardless. ... all of this is assuming we have free & fair Federal elections again.