People also commonly forget that Obama ran on a platform of Hope and Change. What he did in office was a sharp betrayal of what he promised voters, but Obama's success was a clear indication that Americans (Republican, Democrat and otherwise) did want change. Trump also ran on a campaign of change (admittedly a horrific vision of change). Trump, unlike Biden, delivered. Roe v. Wade is dead and a bunch of other progressive rulings are on the chopping block. LGBT rights are down the toilet. That might be more the work of state governments but Trump will claim those things as his wins.
This story indeed starts with Obama's betrayal of the "Hope and Change" he sold.
Obama is a character that ought to be studied carefully. His is very much a product of inbred american elites, regardless of race. Parents were probably CIA or close to it, with cover stories. Obama was the high tide of the takeover of the state's politics by a portion of its permanent bureaucracy. There is always promiscuity in politics with the permanent bureaucracy, in any country and type of politlca regime. But the US centralized, the bureaucracy grew in numbers, and this promiscuity got more pronounced there ever since WW2. The result, in any country, is always an emptying of democracy: the ritual of elections remains but the policies are decided and enacted regardless of what the voters want.
Thus the betrayals by Obama. There would be no change. He represented the existing trend winning again. Betraing all electoral promises and immiserating citizens while bailing out the wealthy, during the crisis.
Trump was the reaction of the voters. Which was regarded as high heresy by the permanent bureaucracy, for what he
said even if not for what he managed to do. They chose to rally for a reaction in the Democratic Party, as dictated by the dual nature of US politics of the time. The bureaucracy never forgave the sting of losing to Trump, hence the lawfare during his term, and now to prevent any repeat of that, a continuation of the fight since. In this they turned the Democrats into the party of the permanent bureaucracy, and consequentially eased the takeover of the republicans by an apparent, and to some degree real,
opposition to them. The "populist" faction now has much firmer control within the Republican Party, Trump is running an organized and well-backed campaign this time.
The Democratic Party has turned its back on the
deplorable population of the country. As it eagerly allied with the offended state bureaucracy, it inevitably merged with it, with its interests. Politically that will either lead to its failure as a
democratic party, or a supression of formal democracy in order for it to take and hold power. Because a party openly allied to a (by definion) small elite and its interests
cannot be popular and win elections. The Democrats are attempting to be
politically competitive by relying on the faults of their only rivals (the Republicans), public disinterest in politics, and advantages in propaganda and cash spent. This only works if the system is so controlled that "the alternative is worse". In a real democracy there will always be rivals winning populatity and beating them. Long term, this "merger" of the party with small elite grups and their narrow interests as a class causes its failure as a competitive party in a democratic regime.