I think people rightly don't believe it because it's apparent that the economic machine in the United States is not built for the benefit of the average worker, it's built for the benefit of the capitalist class that's captured the government. Republicans may be more up front about upholding the status quo, but there are plenty of corporate Democrats that will support the same status quo while chasing the social capital that comes with agitating for change that more progressive groups are pushing for.
People don't have faith when they're constantly sacrificed at the altar of "the economy" without seeing any of the benefits of an improving economy. For a good example, look at how the BNSF rail strikes were resolved before Christmas last year. Rail workers were striking for very reasonable things like 7 days of sick leave per year (up from literally 0, per the contract they had with BNSF) and appropriate staffing to prevent emergencies (like what happened in East Palestine, Ohio in early 2023), and what did Biden do? Biden, the guy who campaigned as one of the most pro-labor and pro-union presidents in recent history, stabbed them in the fucking back and made it illegal to strike because an unstable supply chain around Christmas spelled "economic catastrophe". Biden would rather go to bat for a large corporation than for the workers that corporation is shamelessly exploiting.
The pandemic is another great example. "Essential workers" were expected to risk their lives and those of their loved ones while business owners got huge loans they never had to pay back. Working folks meanwhile got a couple grand for the entire year and even then folks say it was too much.
I've never seen such a naked upwards redistribution of money in my life. At one point, the Fed gave itself the power to literally buy shares of funds itself to inflate the price.
Now since the free money has dried up with rising interest rates (which had to happen because the poors were finally seeing an opportunity to get a mortgage with low rates and that caused all of the inflation don't you know) businesses are raising rates on everything ever to sustain their profits.
Except the term "essential workers" became a hollow statement when it became obvious that it wasn't referring to "essential" to society, but essential to the economy.
Nurses and firefighters, hell yeah, but also bartenders? Oh, but definitely not restaurant servers. Oh yeah, but we gotta keep those Walmart baggers on the Frontline, can't risk cutting into the Walton's fortune.