The democrats - 48% of the electorate - would vote for a Russian dwarf hamster for president if it were running as a rat. I’m not concerned about them. It’s the 5 or so percent who might swing either way.
Trump can boast a good economy. Obama has nothing to offer but a reprise of the previous administration, which people basically rejected in 2016.
I see things a little differently. Michelle is a black female who was a former first lady of a President that was very popular with the DEMS, who managed to make the GOP(e) ineffective, inept and controlled Mitch and Paul and he had a tight grip on the DOJ. The MSM still remains fixated on the Obama's, more so now on her. IMHO, it was the MSM that got Bammy elected and I don't doubt for a minute if she decides to run, that is who they and the DNC will get behind.
Hillary ran a sloppy campaign as she thought she had the election in the bag and didn't have the stamina to sell herself to the millennial. Michelle on the other hand has been active with speaking engagements, writing a book and in the media spotlight since she left the White House. She certainly has the millennial behind her and also the stamina needed to run a vigorous and competitive campaign. Oh, and she has the money.