Given the 'great leftist fear' sweeping the country, I would expect somebody to publish a study proving a progressive can't win. I haven't seen anything like that and a quick google search didn't reveal any studies of the 2020 election authored by Dr. Benhabib. The conclusion is, to my way of thinking, counter-intuitive. All the fundamentals strongly favor the Democrats.
Turnout in the 2018 election was huge in comparison to typical off-year elections and that increase has been attributed to the following groups: young voters (18-29, 15.7%) (30-44, 13.2%), Black, Hispanic and Asian voters (10.8%, 13.4%, and 13.3% respectively). To put this in context, it means that these groups voted at a rate comparable to general election turnout figures in an off-year election. The dynamics driving that turnout haven't changed and the turnout next year will be higher than it has been in decades. A forty seat gain by Dems in the House is indicative of a wholesale rejection of republican policies and leadership and it strongly suggests a political realignment is in progress.
For example, the Dems flipped seven seats in California. In four of those districts the Democrats now have a lead in party registration. In the district in Orange County won by Katie Porter, Republicans had 14.2% edge in 2016 which dropped to 4%. in 2018. The republican advantage in Devin Nunes' seat (Tulare) has been cut in half as has the Republican minority leader Kevin McCarthy's seat next door in Bakersfield. These are seats that were gerrymandered to ensure republican control for eternity!
Sixty percent of voters think the country is on the wrong track, a figure comparable to the a year before Obama was elected. Fifty percent of voters identify as Democrat or leaning Democrat, the strongest lead (8-10 points) Democrats have had in years.
The above numbers indicate tectonic shifts in the electorate. In 2018, republicans lost some of those who lean republican and the loss was greatest among republican women. When I started writing this I thought I had figures on the suburban vote by demographic group, but I can't find them now. I doubt that educated republican leaning women in the 'burbs who went Democratic in 2018 will revert to their old ways regardless of the democratic nominee, not when the republican candidate is Trump.
I also expect the Democrats to balance the ticket. A Warren/pick your favorite moderate ticket will calm potential defectors. I should note that Biden said he would pick a moderate as his V.P. about two months ago. It was one more in a long list of cringe-worthy, and just politically stupid, comments.
I think this will be a brutal campaign unlike any other I have ever experienced, and frankly, I am not sure that any of the democratic candidates have figured out how to manage the phantasmagoric swirl of Trumpian bull that seems to overwhelm reason all too frequently.