Also everyone is leaving the party, I imagine party heads are seeing the data and wondering what to do.
As Eitan Hersh proved over a decade ago, most voters are already decided so a reduction in party membership didn't have much of an impact.
The biggest issue has been organizational. The best example is probably the GOP after Obama 1.
Ironically, lower civic engagement might actually help the Dems given the demographic shifts over the past decade.
At this point elections are won based on whether or not subsegments of the population can be rallied to show up or not show up to vote in elections.
This is becuase in most elections, most voters simply do not follow the news, and if they do it tends to be a quick video or a listicle.
Thus, the voters that can swing an election are those that are part of organized voting blocs (eg. A specific union or a local PTA), and cultivating those local groups and ties matters more.
2024 clearly says otherwise. They won't vote for R's, but they may also just not vote at all. That's almost as dangerous. The DNC definiately needs to energize its base again, not just say "well we aren't Trump".