He would've won. Whatever his faults as a candidate are, he's better than Barnes and that probably would've been enough to win by less than 2%. Not sure why anyone would think that there'd be all these Barnes voters switching over the Johnson purely because they're angry at Feingold for losing in the past. That doesn't make much sense to me.
He wouldn't generate enough turnout like Barnes did specifically because he's lost twice. Self-fulfilling prophecy in a way.
I don't know that I buy that. The race likely wouldn't have been written off the way it was with Barnes if Feingold had been the nominee, plus Evers' reelection would've driven turnout too. Although to be fair, Barnes probably would've won if the Democrats had known to take that race seriously in the first place. But I just don't see the reasoning behind the notion that all these voters would stay home because Feingold lost a couple times over the course of 12 years. It's not like he's run for the same House district and lost multiple times in a row.