I agree that those are all factors but I don’t believe you can solely boil it down to those three. With the manifesto, leader and messaging in place as they were, I genuinely don’t believe Labour would have won if none of the three things you mentioned had been an issue.
I have literally no appetite for either defending or criticising Starmer right now, I don’t think he’s interesting at all (which is probably more of a good thing than a bad thing atm, but it’s a fool’s errand to try and predict anything these days). I think I agree that he’s not well equipped to deal with the issues you raised, but I don’t really believe that of any of the leadership candidates.
I absolutely believe that the decay of trust in the party within ‘red wall’ communities lies with New Labour rather than Corbyn, even if it took until 2019 to totally fall. But I can’t say I’m looking forward to 4 years of Yvette Cooper poll gotchas in these threads and visions that the Corbyn revolution was foiled only by the media and Brexit and none of his own, the party’s own, and the campaign’s own shortcomings.