That theory would rely on her being (or having become) self-aware. Remember, this is the same person that publicly said "For the first time in my life I'm proud of my country." I just don't think she's bright enough to have had that epiphany.
Maybe she is "reinventing" her image. One of the subtleties of being Barry's FLOTUS was not upstaging him in matters of State. I'm sure that took an effort, even for her. If She is tapped to run, though, the gloves are off and she can make choom boy look like an idiot (with help from the handlers, of course), planting the seed of thought that if you liked Barry (and many did), she will be SO much better.
A makeover, some decent clothes that don't look like they were made from material salvaged from drapes or breezeway furniture form the 60s, and some charm school work (much already done by coaches in the party, protocol office and the press) and she'd be polished enough to swing a chunk of the vote. Add in the BFF (Black Female Factor) and genuine 'minority status' (as opposed to Fauxcahontas' shaky claim to being "Indian", and she'd be a superior candidate for the candidacy.
Considering the white liberals are often the holdover peaceniks and/or philosophical and/or physical progeny of the whole 'antiwar' movement, her positioning herself as the "peacemaker" might attract a contingent of gray ponytails who might not otherwise vote with her, would appeal to the woman's vote sector of the Liberal faction, and carry the minorities, with the Latino community being the one wild card, likely appeased by immigration policy (not counting what I believe is a growing fraction converted to conservatism, capitalism, and the idea that truly being able to make your own way and keep most of the proceeds is a good idea).
The 'kids' she played to in commercials on the Disney Channel will be able to vote, if not in this election, in the next (2024) and this may well be positioning for the ticket.
Who else do the Dems have?
An aging white Socialist running on "free stuff".
A person who may well have fraudulently claimed minority status to get into college and gain other perks?
Schumer? > SPIT! < Pelosi? (return of the Mummy) Feinstein? (the 'give up your guns' lady?)
"Foreigner" Biden (with Russian hands and Roman Fingers), especially on the young pretties? After the Moore and Kavanaugh gambits, how would that play?
An assortment of also-rans and people who would barely carry their home districts?
No, they need to groom someone and quick.
She is the likely best positioned in the herd.