Yeah, that’s not how it works. It’s a comforting liberal illusion but, as with all things liberal, it entirely ignores how power works.
Labour members did it with Corbyn, after the Blairites fucked up by believing their own bullshit. They almost fucked up again in 2017 by mostly shutting up as soon as the election was called, believing the destruction of Corbyn was inevitable, and more convincing if they didn’t have an obvious hand in it. That gave us a shock result, with a hung parliament despite the Tories starting 15-20 points ahead. So they and their billionaire mates made sure they buried him (and us) properly.