Since you made the effort...
The biggest single issue that I don't see Sanders overcome in the G.E is his tax plan. No one has ever won the presidency on a tax-raising on all income levels platform. Sure, McGovern's loss can be chalked up to intraparty fighting, but Mondale 49 states defeat is the model we are talking about. Despite the changing social norms, Americans don't take kindly in paying more taxes and having more government oversight (get off my healthcare!!!). I think he can run a competitive campaign against Trump but the latter despite his demagoguery can still occupy a somewhat centrist position due to his extremely elusive positions, while Sanders doesn't have that luxury. Such scenario doesn't happen with Clinton because you just can't out-center her.
The second thing is the make up of the electorate. McCain was not an inspiring candidate, got mired with W's dump and had the media whack the shite out of him for picking Palin. He got 46% of the votes.
In this age of partisanship, I don't buy the argument that a candidate as extreme as Sanders can entice Republicans to vote for him, and while he does well among independents, it's worth noting that the GOP primary turn out have been consistently higher this cycle. Independents are themselves not all centrists, in fact most of them have a political leaning considered fringe to both Parties. So there's a more than good to fair chance he will lose the centrists, motivate the far right to turn out while only carry the far left himself. This argument is supported by his losses in all the big swing states so far (OH, FL, VA).
And finally, assuming that against all odds, he beat Clinton fair and square to the nomination, carry the general and take back the Senate, you still can't take back the House and State legislatures this year. He will get gridlocked to death and in 2 years the GOP will read it's head again. A President Rubio or Cruz in 2020 will pretty much mean that all states legislatures, majority of governorships and the House remain in the GOP's control for another 10 years. Is that a risk you are willing to take? Clinton will take her half loaves, but she'll at least have something tangible to run on. Political revolution doesn't sound as appealing the second time after 4 years of no achievement.
First of all, if you start with snark, you can't expect better in reply.
About the rest of your post:
You can't have it both ways.
In paragraph 1, he's Walter Mondale II, able only to hold onto Vermont while the rest of the country resoundingly rejects him. In paragraph 3, higher partisanship means constant voters (and safe states). So are you saying MA, for example, will abandon him for Trump?
Secondly, I get that his numbers will fall. Have you checked his numbers of late though? It's +16.5, +10.1, +2.7. The 1st 2 aren't razor thin elections decided in Ohio. These are in fact the kind of blowouts you are suggesting he will be subject to. And these numbers have
improved throughout the cycle. He started off negative v/s Bush ffs.
So, yes, he will fall. How much of that (ENORMOUS) lead is going to be lost to Repub attacks? How many women are going to vote for Trump? And moderates for Cruz, who shares his stage with gay-killing advocates? Have you seen
their numbers of late, and this is without the Dems having to touch them with a single attack...
I think Kasich will beat him - but he will clobber Hillary, so it's best not to think about it. He is the only candidate with favourables approaching Bernie's, he has a lock on Ohio, and is seen as moderate by the media,without her baggage.
Bernie's losses in swing states happened on the backs of Dem voters, not independents. He won more independent support than her in Ohio for sure, and I think FL* and VA were closed. Again, are you saying Dems will stay home when Obama, etc. hammer home the message about the enemy - Cruz or Trump? At the same time as you're talking about polarisation and people not abandoning their parties...
I was told by Ubik/you some weeks ago that turnout means nothing. Just as I was told that H2Hs are non-predictive. Right uptil now, when turnout means something and H2H trends are important (but his are not). As I said before, there's no problems acknowledging love for centrism, and for her. Now you enjoy her growing lead over Trump. But dismissing the amazingly consistent numbers he's generated in the very same breath is hypocritical.
None of the discussion has been about his presidency. I wrote that I don't expect his domestic agenda to pass (unless the Sanders-Trump numbers hold, and he gets all 3 branches). I expect that he will not compromise on pipelines. And I expect that he will be a restrained commander-in-chief. Both those things are to do with executive actions, and both are areas where I'm confident Hillary will make the wrong choice. Based on his public statements, I also expect him to defend Roe v Wade without compromises, while she has indicated a willingness to undo a
somewhat landmark decision.
I have no idea why you think that she will win re-election in 2020 (or that he won't). That's just pure speculation. I can speculate about the orgasmic prospect of him winning, stepping down in favour of Warren, and her winning 2 terms for 12 years of progressive rule. I can speculate about how a politician as loathed as Hillary will do in the general when she's not up against an orange misogynist douchebag. But I have no idea what will happen.
*He isn't winning FL anyway though. It's demographically all wrong for him. On the other hand, the H2H polls released during the Utah and Arizona primaries were interesting, and, of course, he was doing better than her due to independents. Ohio was bad for both, which is alarming.