They aren’t all “young socialists.” A LOT of Bernie supporters are blue-collar Dems destroyed by free trade.
So, yeah, the general electorate is much different, but I think (and many Dem pundits have agreed) that Trump and only Trump represents a threat to capture these voters.
Again, the fact that in OH, coming in second, Trump beat Cankles by 35,000 votes is quite significant.
Sanders prescriptions are leftist. There are certainly some blue collar old school Democrats who support him.
But, at the end of the day, if you are voting for leftist solutions, you are a leftist. Or wildly misinformed.
Example, you may want to help people, but a higher minimum wage doesn’t do that. Sincere intention, bad policies.