I think the Vox article, though it does rely on a lot more conjecture than it can prove, has a ton of salient points. The Democratic Party has abandoned a tremendous portion of what was its New Deal constituency, favoring college educated upper middle class suburban voters, and hoping minority support will always be a given.
In what smug liberals would refer to as the horseshoe theory, as a leftist I'd suggest I agree with the conservative viewpoint the article posits that the mainstream Democratic Party isn't offering material advantages to many of their erstwhile voters. I listened to an interview with India Walton, the dem soc Buffalo mayoral primary winner, and she laid it out similarly to how Republicans describe major American cities under generations of Democratic rule--have conditions improved? Are streets, sewers, and sidewalks in better shape? Is violent crime down? Are schools better? Of course where I part from conservatives is in the solutions, but we can both agree that neoliberal Democratic means tested lukewarm policy isn't it.
I disagree with some of the causes the Vox piece identifies for this (such as The Daily Show), though I know that some of my most smug and self-certain liberal friends find solace in shows like TDS or with John Oliver or even the late night jabs at Trump from Colbert, milquetoast as they were. I think the Jon Stewart version of The Daily Show at least set its sights on the media at the same level it took on any administration--we don't really have as cogent a discussion of media devolution elsewhere today. Instead, the article correctly diagnoses that Facebook and other online forums become echo chambers for confirming one's own bias. If you click one type of story, you'll continue to see that kind of story algorithmically served to you.
I would say that what the conservative side of this argument misses is that elites in both parties lie to their constituents, and the other side of this smug liberalism is fake folksy populism on the right. While all these lowbrow talk radio conservatives are dying of COVID along with their anti-vax messaging, their TV counterparts are saying the same stuff but you know they're all vaxxed to the hilt. Any Hawley style "worker led conservative movement" is a huge grift. They don't want workers to own the means of production any more than a smug lib would, theirs is still a purchasing power, market based solution to inequality that will always face the same structural problems as neoliberal solutions will.
But dismissing the Vox piece today feels pretty short-sighted.