I would have been stunned if he didn't win the momentum behind him was massive, Reform hasn't gone away smaller parties including the Tories came nowhere.
There is every reason why MPs rally round Burnham and depose Starmer immediately, they obviously want a change so why wait until after the summer break. Burnham "talks the talk" and should unite the Labour Party whether he can score enough successes to win the next election will be the real test.
I just watched an interesting analysis on Sky News. There was a higher turnout than in the general election for this by election, which is apparently almost unheard of. With over 55% voting Burnham it was decisive.
Maybe or maybe not but, by keeping the Personal Allowance Threshold frozen until at least 2031 Ms Robber Reeves will ensure that the fiscal drag mechanism will claw back any benefits of the Triple Lock via Income Tax.