Christ! Being a liberal is easy isn't it.
Firstly just to get it out of the way, Mcdonell literally apologised for the election result on the Marr show last week. So the idea that the left of the labour party is ''devoid of humility and honesty'' is just untrue
Anyway moving on from this bizarre moralism and onto something that looks like actual politics. You quoted a tweet I posted yesterday showing everyone over 65 hates not just Corbyn but the Labour Party as a whole. So simply getting in a new guy as leader isn't going to change this and neither will the current view the left has, which is going into these communities and do local organising(Putting on a bingo night in Bolsover isn't going to stop 70 year old Bill from thinking the labour leader is an ISIS loving communist who wants to crash the economy by giving away free stuff).
So whats your answer (The best I've come up with so far is to turn and expand Manchester into a giant blade runner city) ? Please don't just say, the new labour leader should be more racist nationalist while holding an England flag.
Corbyn legacy will of course be in part this election lost but it will also be turning the Labour into one of the biggest centre left parties in Europe and putting forward a manifesto that took seriously the dangers of climate change(And it possibly still didn't go far enough). I've yet to see any centrist/liberal politician put forward a plan to actual address the biggest issue of the 21st century. Not only does there seem to be no policy(Or at least policy that isn't constantly undermining the fight against climate change - the Canadian guy who loves doing black face and building pipelines, for example.)there seems to an active disregard for left policy, if liberals are laughing at the idea of planting 2 billion trees in 20 years, then they are no different to the american president who believes climate change is a hoax.
Its one thing to have a political platform that is hated by anyone over 65(Which is a massive problem), its another to have a platform that will utterly fail to meet even the very basic challenges of the modern world.