I actually thought something pretty much like that in the time after I posted, and came back to say as much, so you've saved me the trouble.*
Hillary went down in part because right-wing media had demonized her for decades. The left has taken note, and if there's no reason to assert yourself, don't.
And I think it's working; all I've seen the right go after Harris for is her laugh.
Generally speaking, it's better in a lot of ways to be a blank slate. Two of the last three three successful presidential candidates have had that going for them.
I'm starting to sneak Katie Porter's name into these lists, when they come up. Where's your Newsom?
*That's why I relish the occasional opportunity to debate with you; cuz we generally see eye-to-eye on most things.
I think I'd put Newsom in the "won't run against an incumbent Democrat category". It seemed in 2016, all the serious Democratic candidates, were effectively treating Hillary as the stand-in incumbent, in Biden's place, when Biden declined to run.
Now Newsom had no such obstacle in 2020, unless you wanted to treat Biden as a sort of delayed incumbent, having previously served as POTUS and skipped the election when it really was "his turn" to run. I suspect that in addition to grief over his recently deceased son, Biden was also deferring to Hillary, basically giving her another shot. But no one else gave Biden any such deference in 2020, until it became clear that they had to rally behind Biden to prevent Bernie from winning by stubborn plurality, the way Trump had done in 2016. So its unclear to me why Newsom hasn't run yet, particularly in 2020. Maybe he's got some scandal that he doesn't want dredged up? He was formerly married to Kimberly Guilfoyle, so she certainly has dirt on him, and she is famously now engaged to Donald Trump Jr., so they won't hesitate to use whatever she has against Newsom.
If you'd care to put on your Pym particle suit and step into the Multiverse with me, I've been considering some "What-If" questions I'd like to ponder with you...
What if Al Gore had won in 2000? Would 911 have still happened? Afghanistan war? Iraq war? Assuming baby Bush was nominated again in 2004, would Gore have been re-elected? Would the 2008 financial meltdown have still happened?
What if Hillary had run in 2004? Would she have won? Assuming she won, would the 2008 meltdown still have happened? If it did, would she have been re-elected?
What if Hillary had won in 2016? Would the COVID years have been much different? Would there have as much unrest and social upheaval, lockdowns, and all that death and misery in the US? If there was, would she have been re elected?
I have more, but even the ones I've posed contain many permutations and variations so I'll stop now before I travel any further into the weeds.