I don't think that's the case.

Sanders ran on a platform that did appeal to the white, blue collar voters - much more than Clinton did, at least. If you look at the numbers, the turnout on the GOP side of the election was pretty much identical to the turnout in 2012. The election was lost because Clinton failed to energize the base Obama was able to in 2008 and 2012, to a lesser extent.

The addition of Sanders wouldn't cause a loss of these blue collar voters- the blue collar voters "lost" by Clinton either voted for Trump, or abstained altogether. Having Sanders on the ticket may have energized that side to vote - his message was one that should surely resonate with them. Instead of blaming the class woes on immigrants and outsourced production, he blamed it on Wall Street and the 1% - I fully believe the working man would have no problem buying into such a message.

The problem with this ticket lies in the fact that the message Sanders has tried to project becomes hypocritical when he's paired with Clinton on the ticket. Anyone could easily see that even though Sanders would be authentic in staying true to his mission, his presidential pair would be one beholden to corporate interests. I think that would be the principle limiting factor of such a ticket, not his socialist ways.