I have zero idea why you think that. I have stated numerous times on here that Corbyn was too right wing for my liking, but Starmers idiotic treatment of him will cost Labour votes.
The polls are narrowing, Sunak is doing better than expected, the Johnson fiasco will be over and the Tories are the best party in the world at reinventing themselves.
Plus the Tories have the all powerful media onside, the Labour party is uninspiring and the electorate apathetic, the they are all the same narrative suits the Tories. Voter ID hit Labour support more than Tory support and in UK elections incumbency is King. The Lib dems will make gains at the expense of both parties, and whilst the SNP is imploding there is no guarantee of gains for any party.
To an extent as well 50p Lee is right, the nest election will be fought on culture war issues. The Liberal left have no answers to the Tories on those matters, because they rely on identity politics and the real war is the class war being waged against the working class. Labour sadly have no answers and the working class know that.