Except that it's not fealty. The DNC and the power brokers don't give a damn about Biden specifically.
It's shallow and ill-considered self interest.
If Biden steps down, then that opens up the nomination process, and as they've done the last two times, the rank and file are going to want a progressive. If anything, the call for a real progressive is going to be even stronger than it was in 2016 or 2020, in part because so many on the left have been disilliusioned by Biden's mealy-mouthed criticism of but tacit support for the Gaza genocide, and likely even more because Trump and the fascists riding his coattails are an existential threat not simply to progressive causes broadly, but to progressives personally.
But a determined call for a progressive candidate is the last thing in the world the DNC and the power brokers want, since a sincere progressive is going to alienate some number of big donors, so undermine the ongoing flow of soft money. And that ongoing flow of money matters more to the DNC and the power brokers than anything else, including winning or losing.
And at this point, so much of the mood on the left is so strongly against the neoliberal hacks that if they try to do the same thing they did in 2016 and 2020 and force a neolib hack on the voters anyway, it's likely that they'd end up pissing off so many voters that their candidate will do even worse than Biden would've done.
So the "logical" (in a very narrow and warped context) thing for them to do is to stick with Biden, and likely lose.
And in fact, losing and then fundraising in their role of (supposed) opposition is pretty much standard operating procedure for the Dem hierarchy - that's a role in which they're obviously comfortable and that they'd undoubtedly expect to just slip right back into.
The thing is though that this election is different. This isn't just a choice between two slightly different flavors of neoliberal establishment hackery - this is a choice between safeguarding democracy or inviting the wholesale destruction of democratic institutions and the establishment of a fully empowered hate-fueled right-wing, plutocratic oligarchy. The Dem elite will quite likely no longer be able to fundraise on being the (supposed) opposition because opposition will be effectively prohibited.
So it's time for them to make a hard choice - to potentially sacrifice their own unearned privilege, basking in a sea of soft money, for the needs and desires of the people whose interests they're supposed to be furthering. And really, though they're likely unable to see it, fir their own long-term interest as well.
Unfortunately, I don't think they have the necessary integrity or determination to make that choice.
Party leadership was worse than dubious when, following the debate, House Democratic power broker Rep. James Clyburn of South Carolina intoned: “Let’s just stay the course.”
ah, yes... the same james clyburn who put his finger on the scales during the hotly contested '20 primaries between biden and bernie. yes, that clyburn.