Based on what empirical evidence?
The DCCC and the DNC have routinely chosen to support candidates that consistently poll lower than progressive candidates. They've chosen candidates that have gone on to lose to the Republican in the general while actual progressives won by supporting a progressive platform
Hoyer and the members of the DCCC back candidates they know will be soft on issues that undermines their donors interests like campaign finance reform and universal healthcare, so those donors/industries will continue to financially support the Democratic party in the exact same way the Republican party supports the NRA. There are no instances, not even one, of the Democratic establishment endorsing a progressive candidate over an establishment friendly one. Shouldn't it be pretty easy to prove that claim wrong if it was false? That fact alone suggests your claim is wrong
These are not "political groups", they are sitting politicians who are putting their thumb on the scale in elections and changing laws to ensure they remain in power, the consequences of which result in a weaker middle class, an inefficiently run economy, wage stagnation, massive debt, and dumber Americans. Special interests, both right and left, have bought individual members of our government in order to ensure they protect their interests. It's not about what idea is better or how many Americans support it. It's about how much money you can donate. Many American politicians are not interested in their constituents interests, they simply push a form of identity politics depending on which party they're a member of; Democrats push gender identity politics, racial identity politics, issues that are safe since they don't affect their donors interests since Democratic party donors generally support those issues. That's not to say those issues are not important, they are, it's to highlight the reason why some issues that would seem like no brainers to most Democrats get party support and others don't. Republicans push religious identity politics based on traditional conservative values, gender/sexuality identity politics, and also racial identity politics. They push the 2nd amendment while denigrating the 1st, a free and open press.
The Princeton study frequently cited shows evidence that 95% of the time, the candidate who spends more on their election wins. Elections shouldn't be decided by who spends more, they should be decided based on the votes from candidates without external interference from the party influencing the outcome.
