I have been hammering at this point for a while. I've tried to figure out where he has gone and stumped for other candidates. The only instances I could find (not saying that they are the only instances, but they are what I could locate) was to campaign for Jesse Jackson in 1988 and to campaign for a Vermont Democratic governor candidate a few years back. I can't find any cases of his actually going into another state to do so. He doesn't tend to mention local Democratic officials at his rallies either - I suppose he may do so, but I don't think he bothers much about it. Hillary, OTOH, has been out and about campaigning for fellow Democrats and raising money for them for years. She should have mentioned during that Flint debates that she actually came out and campaigned for Snyder's opponent in 2014. Where was Bernie?
His supporters can whine about super delegates all they want, but most of them are friends and colleagues of Hillary's, and she's provided support and fundraising heft for them over the years. You are exactly right that Bernie has not helped Dems out in the past and he doesn't seem to be doing anything for them now, either.
I thought his answer to that question was absolutely ridiculous. Even in a best-case scenario, he would have to deal with a GOP Congress. Voter turnout alone isn't the answer because gerrymandering is so rampant (and, Hillary's lawyers are actually actively involved in getting some redistricting in Florida and Ohio even now).