You keep telling yourself that.
200,000 following his initial election to Leader. 60,000 since the (pretty much bodged and failed) Blairite coup began.
He's appealing to sections of the electorate that have been roundly ignored by the other parties - and Labour's performance since his election hasn't shown any signs that people have abandoned them because Socialism.
Held every seat, gained Mayors, ultimately won the local council elections.
The media really need to stop with trying to paint him as a failure when he's anything but.