That's not how political parties work, though. Political parties are largely ideological institutions, they exist first and foremost not to win elections but to propagate an ideology, and winning the election is just a sign that they succeeded in their goal of convincing people of their ideology, and so now enough people agree that it can take root in the state. When political parties lose, it's very rare that they will interpret their loss as "we need to abandon all our values to match the opinion polls." No, they interpret their loss as meaning they failed in their goal of convincing people of their values, and thus should change their strategy of their out-reach, not changing their whole ideological position.

Democrats going against the rich elites would be an abandonment of their party's values and everything they stand for. In most countries, if you dislike the ideology of a party, you vote for someone else. The party itself has no obligation to change its entire ideology for you, such a thing very rarely occurs. If that was the case, then every political party would all have the exact same position, just all copy/pastes of whatever the opinion polls say.

I keep seeing all this bizarre rhetoric about how if the Democrats were "smart" they would just abandon their whole party's platform and adopt some other platform, but this makes zero sense, because you have to consider motivation. Their motivation is not to just win the election, but to convince you of their ideology, and abandoning their ideology does not achieve this. Democrats are not stupid, they just don't have the same motivations as you. Yes, they want to win, but they ultimately want to win on their platform, not on someone else's platform.

That's how political parties work. They have a platform, and the platform is paramount. If a green party adopted all pro-coal and pro-oil lobby positions just to win an election, that would not be a "smart" decision for them, because, even if it leads to their victory, it still is an abandonment of their ideology. Democrats are unabashedly a pro-rich elite party, it should not be smart for them to become anti-elite, because it is not aligned with their motivations.