Have you ever asked yourself why this failed if it was so attractive?
I agree a lot of what JC put forward found favour not just with Labour voters but elsewhere, in many cases because anything was better than what the Tories had delivered.
It failed because he/or his entourage tried to put forward too much; at first people were interested, then as more and more ideas and promises rolled off JC's bandwagon, the reaction changed, the realisation became that this was impossible to achieve.
It then became a situation where the uninitiated began to ask... "are these people living in the real world." There was a point when crucially the ones who questioned this momentous itinerary, who also occupied the voting positions/constituencies who were enabled to deliver a Labour victory, decided this was 'beyond the pale' and the vote for Labour in the crucial areas never materialised.
It was classic Labour 'fumbling' at the important moment. Starmer came in and put that right, he used the obvious message that 'anyone but the Tories' would play out so too he added something more attractive. 'we need change'. Which of course everyone agreed with, who wouldn't at the stage?