Except Harris would have won if she got the black vote and latino vote. Compared to the results in 2020, Harris lost black men votes to Trump in Philadelphia, and lost Latinos votes across the whole country (men and women). A LOT of latino voters shifted to trump, even the Puerto Ricans in PA. White votes didn't change from 2020.
The failure was, as it always is, the economic message. Despite the US economy being strong and objectively better than 4 year ago, two-thirds of people think its worse and that America is on the wrong track. You can't win elections when people think that about an incumbent administration. The voters that shifted to Trump (the minorities) believe their lives will better under Trump than Harris. (The sad irony is that they will almost certainly be worse off with Trump.)