(Part of the answer to why Labour has been out of power for 13 years is the Corbyn disaster, it explains half of that time span).
[0]: https://commonslibrary.parliament.uk/research-briefings/cbp-...
That's why you got stuff like his face getting greenscreened onto a clip of voldemort on the BBC.
One thing that people underestimate is just how far to the right of the general population the media and political class is. They tend to be private school dominated, overwhelmingly drawn from southern england, and personally wealthy.
The situation is not irretrievable in theory, at this point.
The problem is that in practice a solution requires the political elite to collectively admit the falsehood of the axioms they built their entire careers on.
If an individual political leader defects from the nationalist-neoliberal consensus, then they get treated exactly the way Jeremy Corbyn was. Corbyn was a soft-brexiter -- his distrust of the EU was based on it having emerged from the EEC, as a capitalist institution: what they hated him for was for being an unreconstructed hang-over from the 1970s when Labour was actually a left-wing party.
Neoliberal politicians can't admit that the crisis is rooted in neoliberal policies.
Tories have done well to court the people that show up at the polls with things like keeping the Triple-Lock pension guarantee[1].
Like the Democrats, Labour's demographics have started to shift more to the well-educated (though I suspect this will swing back massively, come the next election). This alienated their traditional working class base who care more about their own economic realities than whatever social crusade is the flavour of the week.
Young Labour went out of their way to paint pro-Brexiters as racists and bigots. The dirty secret is that even Corbyn has been a long time Euro-sceptic. Because of the in-fighting on the correct position, Labour didn't take a hard stance on Brexit until very close to the end, IIRC. At which point, anti-Brexit votes were being siphoned off by the Liberal Democrats, with pro-Brexit votes going to the Tories.
[1]: https://en.wikipedia.org/wiki/State_Pension_(United_Kingdom)...
I'm pretty sure that a reason Labour did much better than expected in the 2017 general election is that Brexit voters suspected that Corbyn had secretly voted for Leave.
London has a Labor major and it is the economic Center, so maybe there was a lot of Labor influence on the economy after all?