This is an odd essay that manages to somehow combine diagnosing the problem with engaging in the problem.

Yes - at heart, the problem with the Democrats (and with US politics broadly) is the outsized influence of the donor class. And Reich does a good job of isolating the problem.

But along the way, all he really does is contrast the influence of the donors with the influence (or lack thereof) of other narrow elitist groups - party officials, other politicians, elder statesmen and the like. Other than a passing mention that "The polling data I’ve seen suggests that concerns about Biden’s age and evident decline worry a wide swath of the public," he doesn't even really acknowledge the idea of the public at large having any influence.

So really, his criticism boils down not to a complaint that elites have too much control, but simply that the wrong elites have too much control.