Left wing parties elsewhere are losing too, mostly because of immigration. Meanwhile the welfare states are collapsing in the UK, Canada, France and Germany because the birthrates and lack of economic growth can't sustain it.
I think globally a lot of rich world left wing parties made similar rhetorical mistakes. Essentially leaning into identity stuff without acknowledging working class people’s challenges.
Also to be fair they’ve been in power globally for some time and so are seen as the status quo party, and largely ran as such. People are feeling economically squeezed and therefore voting incumbents out.
So it sounds as if the left are attempting to cater to issues further up Maslow's Hierarchy of Needs than the majority of the voting populace think are important.
That's interesting, because it feels like "the right" (in my experience and whatever left and right mean these days) wouldn't recognise or consider catering to anything above the two basic levels (and to be honest, the 'brutal truth' part of my own personality tells me that anything above those two basic levels is 'cream').
People who worry about the price of groceries or basic car repairs to keep their older car on the road don’t want to hear how privileged they are due to their race (they might not be a minority but they aren’t rich) / how they are destroying the planet (they aren’t flying 10x year) / that kids who took out loans for expensive private college deserve free money (they didn’t even go to college or went to state school) / how democracy is at stake / etc.
It's more than messaging when the rank & file democrats and elite voters walk, talk and breathe this line of thinking. And there are policy choices made downstream of it as well.