What Obama had going for him was optimism, relative youth and uncommon speaking ability. The Democrats might do well with a similar candidate but I cannot think of one though have limited knowledge and exposure.
I don’t give a crap about what Republicans think. My big concern is what stupid-ish Democrats think. There’s a whole lot of people who didn’t vote for Hillary in 2016 because they “just didn’t like her”, based on nothing but decades of Republican smears.
As sad and depressing as it might be, this is clearly a factor that the Democrats must content with.
Hilary was certainly unfairly smeared for being a strong woman long involved in politics. She suffered from double standards and a media pretending to treat two candidates equally.
But the fact remains that she was more intelligent policy wonk than deeply charismatic politician. I know lots of people who supported her, sometimes with the enthusiasm that comes from seeing beef stew as the cafeteria lunchtime special. There’s nothing wrong with beef stew. It’s good for you. But it lacks excitement and younger people might prefer other foods.
But the other fact remains that she was up against Donald Fucking Trump, and only lost because of a few thousand votes in key states. If she hadn’t been the target of decades of smear jobs, that margin of “victory” for Trump would likely not exist.
What Obama also had going for him was four years of Bush II and Dick Cheney. I honestly didn’t think the country was ready for a Black president, but the disgust with Bush/Cheney overrode that.
Ah, if only it were just four… 
And an economy in free fall, which voters naturally attributed to the folks currently in power.
The economy is certainly the number one factor. Had COVID-19 not happened, thus cratering the economy, Trump would likely have been re-elected. Or consider Bush 1.0, who after the Gulf War looked like an absolute lock; it was a running joke that the Democrats were doomed in 1992. Then the economy kept stalling.
OTOH, we have a booming economy (cue pending MSM headline “Why a Booming Economy is Biden’s Newest Problem”) and Joe still can’t get anywhere close to a 50% approval rating.
Every time I think I have the country’s electorate figured out, something new happens that I totally can’t understand.
Simple explanation: the average person is stupid, and half of all people are below average.
Consider my post from last week.
If you accept that a significant number of voters are honestly insane, it starts to make more sense. Literally millions of Republican supporters cannot see the actual facts in front of them, because they are fundamentally irrational and delusional. Millions more can see the facts, but deliberately chose to ignore them because of some fantasy they have about how the world works. This behavior is not normal.
Alas, I have no idea about how to fix a level of insanity this great.
The President completely controls the economy; everyone knows that. Running a casino takes skill, but losing money on multiple casinos takes this to new levels.