Plenty of Democrats are electable.
Prior to the election, 74% of survey respondents said the country was going in the wrong direction. The number one response why was that prices are too high. Voters were looking for a change.
She had ~100 days to try and convince the electorate that she could change things, and she did a poor job doing that. She had no answer for high prices, no answer for immigration, and failed to differentiate herself from Biden. In other words, she was not a change candidate in a change election.
Had Biden dropped out earlier and the Democrats had the luxury of a primary, it's entirely possible someone else would have been the candidate and could have better responded to the change mandate.
Despite her poor performance, she still was extremely close in the "blue wall" states -- losing WI by only 30,000 votes, for example.
The American electorate has become increasingly fickle. I fully expect the undecided middle to move away from Trump in 2026 if he hasn't lowered prices and deported millions. He did a poor job of keeping his campaign promises last time, there's no reason to think he will do better this time.
Trump is a once-in-a-generation talent when it comes to communicating with the electorate. I see no evidence that Vance, Ramaswamy, Haley, or any of the others will be able to take up that mantle in four years.
In other words, enjoy the victory, but don't get too cocky. Things can change fast.