YouSir
Retired from Urban
This is certainly true, but it’s not the only factor. Corbyn was deeply unpopular after four years of carpet bombing by the press, but also unpopular with many people who would instinctively disbelieve anything they wrote.
You can argue that this is simply permeation of their influence, but he had too much baggage and no sympathetic story to hawk. These are considerations. Can Starmer present himself as likeable or trustworthy given a bruising career? Would for example Rayner’s personal story play better? Not that these things matter so much if no candidate has the competency for the other demands of the role.
Johnson's personal story is that of a bullying, arrogant, racist, posh, corrupt, lying incompetent given only the barest of whitewashes by some panel show appearances and avuncular bumbling.
And Corbyn's initial presentation was as a decent, honest, not quite Jimmy Stewart do-gooder for a fair portion of the press/party. Right up until he started winning anyway.
A backstory is only as relevant as the spin makes it and only as good as press and politicos allow it to be. No point judging a potential leader on it.