We've heard this before. Given what the Trump Primary Deniers have suffered, I'm not putting my money on the Trump General Election Deniers' prognostications.
Donald Trump, I believe, can get the attention of enough of the independent and Democratic vote to win. He may not, but he can, and given what he's pulled off so far, that isn't a radical statement.
Actually, yes it is, for right now, anyway. Winning a Republican presidential primary is far different than winning the general election. Trump didn't just snatch up the nomination amicably, he did it using hate and scapegoating that has offended and alienated very large swathes of the general electorate. Considering just what kind of voters comprise the Democratic party, saying he can win over a sizable contingent of them to win in November is plain crazy talk for the time being.
Also, it's not difficult to attain at least a limited understanding of why everyone was so wrong about Trump, yet so many keep acting like it's a giant mystery and anyone who doubts Trump must be ignored because... think of the primaries?! Just my opinion, but, you should read what people say on both sides of the aisle and try to understand what they are saying, instead of writing them off just because some of them may have screwed up their primary predictions.
Trump is the presumptive GOP nominee right now because folks like Jeb Bush, Ted Cruz, and Reince Priebus got it wrong as to just exactly who comprised the Republican rank and file. They found out that the "movement conservatives" were a mere minority in the party, and that there wa a huge populist swath that could appeal to other types of Republicans better than Movement Conservatives could. Notice how no one calls each other a RINO anymore.
Who's to say, Virginia, that you aren't making the same mistake about the Democratic Party. If you look at Trump's position on trade and foreign policy, he's a lot closer to Bernie than Hillary is, and this isn't a secret. A lot of folks like me are, in fact, independents, but registered in one or the other major party. I'm a registered Republican, and I tend to lean Democratic, but I vote in every Republican primary, and there are lots like me who are not real party stalwarts, but who are in agreement with Trump on trade, immigration, and foreign policy. Trump's positions are closer to Sanders' position than Hillary's on those issues. I think that there are a number of Sanderistas that have the potential to vote for Trump on issues.