Look at the last handful of democratic presidential losses to see this in action:

Gore gets nominated due to familiarity. He has the charisma of a warm sponge. He loses (barely, and not the popular vote; by the way, FUCK the electoral college) to George W. "I'd have a beer with him and hey wasn't his dad president?" Bush.

Kerry somehow rises to the top of the next democratic primary, a fact that I will never understand, because he also has the charisma of a warm sponge. Bush is familiar and a wartime president. He is re-elected in defiance of God and nature.

Obama comes along and is a once in a generation political talent. Things are pretty good for a while.

Hillary enters the primary and wins mainly based on name recognition. She presents herself as having the charisma of a warm sponge, when we all know full well that she has the charisma of a wood chipper, and since we're pretty good at detecting artifice she loses.

In 2019 we've got a pretty good set of primary choices, but Biden gets into the ring and that's pretty much fucking it, because, again, he has name recognition, so he blows past some better, younger choices and manages to leverage his name and Trump's fuck-ups enough to win.

The pattern is that name recognition will get you a real long way, especially with low information voters, and that is a real goddamn problem when there are objectively better options who aren't as famous.

So anyway, I think we need a constitutional amendment forbidding members of one's immediate family from running for president after one has been president. No sons, daughters, husbands, wives, etc. Fuck dynasties. Fucking fundamentally un-American.