I did not search for such polls, thanks for that. If it is true, what I still find hard to believe is that there is a link between yelling 'I fix it' and the effect on the economy. Economic history teaches that starting a trade war on terms of 'they are treating us badly' or not, has consequences that are bad for the economy. One of the Bushes has tried the same thing and had to roll it back because the heavy backfiring. Yelling 'I will stop this and that war using my charms' doesn't appear to have successful precedent either.
Oh, believe me, I agree with you that the voters have made a spectacularly poor choice if they were hoping to get the economy improved. But that's not the topic; the question is how the Democrats failed to understand the economic hardship of the voting public when it's literally their job to be in tune with voters and why there's still some level of denialism hanging around with Democratic leaning voters about the state of the economy.
I don't think either major party denies the economy is bad or that the public is suffering economic hardship. One just repeats without evidence that only they can fix it, and the other probably can fix it but chooses to do nothing.
The only people who think the economy is great are the top 0.01% who get richer and richer every year, regardless of "good" or "bad" times.
