Here's a video of how the "Obama Coalition" while technically still around and supportive lost a lot of its membership from 2008 to 2024.
He doesn't say it but I think at least one of the biggest aspects is that women, blacks and Hispanics became a bit more socially conservative or not exactly more socially conservative, many were always fairly so, but more willing to outright cast votes based on that. Especially I think more Hispanics voted for Trump despite rather than because of his immigration policies, instead they liked that he was anti-trans and anti-abortion.
I do recall from even back in 2008-'09 white women were basically the last to join, most uncertain about and first to leave the coalition.
Young men shouldn't have voted for Trump but Harris and Walz should have been willing to go on Joe Rogan, for a lot of young people podcasts and going on them yes do seem a lot more genuine and credible.