As most of politics, it's sadly less about actual plans than it is about messaging through catchy soundbites - something the Rs definitely do better. (none that they'd act on any of it) Ds have spent a whole lot of time appealing to constituencies that aren't the working class, with messaging that doesn't work for them.
But it's not just that: Ds have materially failed the working class. They can screech all the want about "the economy" having gotten better under Biden, they're talking about the stock market, which is entirely immaterial to people who can't even save. What is material to them is "non-core" inflation (aka food and gas - it really takes an economist to come up with such a stupid label), which has gone up real bad. And many still remember Obama as having betrayed them by bailing out the banks on their backs, and working hard to save all that rot as status quo.
Yes, D policy would very obviously be better (long term), but a whole lot of working class voters don't trust that to be the case.
Ah yes, the South China Morning Post, a fine outlet to get your opinion pieces on Japan from.