I have been thinking about the whole Manchin debacle quite a lot over the last two days, and I've come to this simple conclusion: Manchin being the sole obstructionist, killing Biden's Build Back Better initiative is the best possible way in which the Build Back Better initiative could fail for the Democrats. Too, the Democratic establishment knew that BBB had no chance of ever passing, so pinning it on Manchin is the solution that will cause the least amount of damage.
As others have mentioned before, the Democratic party has a serious messaging problem. Way worse than the GOP. Other than Biden going back on many of his promises- particularly worrisome in the way that the said purpose of the modern Democratic party is to reassure to its base that government-based solutions can indeed improve one's quality of life, the other main thing impeding the Dems' 2022 and 2024 chances is this messaging issue. The Democratic base is becoming more and more progressive and cautious of money in politics with time, and moderate democrats' share of the party is dying. Literally, as the largest faction of "moderate dems" are the elderly, and many former moderates have become more progressive in their politics, or switched sides altogether. Despite younger and more progressive Dems becoming less patient with money in politics/corruption, only a select few Democrats- the Squad, Bernie (not truly a Dem, but ya know), and a couple others, make "getting money out of politics" a hallmark of their campaign. The Democratic Party and it's higher-ups tend to be quite silent when it comes to the role of plutocrats and dark money in the party. Partly because any major political party needs to secure wealthy donors to remain viable, and an openly "anti-rich" party would fail in that mission, while also because many "establishment" Dems are just as corrupted by these influences as the Republican establishment. The Democratic Party itself cannot seem to meaningfully satisfy it's growing anti-corporate fervor while also not scare off its Koch and Adelson types.
And this is how it relates to Manchin, BBB, and it's failure. In all likelihood, there are numerous senate Democrats who want to see the bill fail. While Sinema (obviously), it is likely that some of the more conservative Dems like Coons, Tester, Hassan, Shaheen, and possibly even Feinstein, would have serious misgivings with BBB. They already were against some of Biden's more progressive initiatives like the $15 min. wage, and are notorious for accepting corporate contributions, so it is likely. After all, it is a significantly more progressive bill than the bipartisan infrastructure deal, and less palatable towards big business. Therefore, putting all of the blame on one obstructionist Democrat- a dinosaur from the most Republican state in America who is already reviled by most Dems, is not only far easier, but safer for the party, than bringing the vote to the floor, where push comes to shove for the rest of the moderate Dems. Bernie had remarked how despite BBB's essential "death", it should still be brought to the floor. This would be done not only to publicly censure Manchin, forcing him to explain to the 73% of West Virginians who expressed support for BBB why he voted "Nay" for provisions like lower insulin/drug prices, child tax credit, Medicare's coverage of eyeglasses/dental, and even a research fund devoted to coal miners afflicted with black lung of all things, but also to reveal other Democrats who could also vote no. Having more than just one or two Democrats who are unequivocally against Biden's agenda- which is just slightly to the left of Obama's ultimately, would be an absolute nightmare for the party and it's messaging. Imagine if it was like the early Obama era and the senate was 57-43 Dem. If big business is really that against BBB, it is possible that seven Joe Manchins would emerge and obstruct the bill, causing it to still fail. My point is simple: Democrats can portray Manchin as the rare exception to the party- which in many ways, he is- to evade blame for their horrible messaging a priori, while also shielding the moderate Dems who could vote no from any scrutiny. The anger, hatred, and impatience would ideally be directed at Manchin, not Biden and the Democratic party.