Every now and then it's required (after extended periods of Tory corruption) that the LP take power - in order to give the impression that we live in a democracy.
Before that happens the LP will need to have a leadership whom those really in charge - capital - can do business with. It's their job, during that period of temporary transmission of power from the Tories, to install a LP leadership who adopt neo-liberal policies domestically and an Atlanticist foreign policy. That's where we are headed back under Starmer, and - outside the rabid elements of the media (the Mail and Express) - he'll get their backing. Expect a bellwether like the S*n, for example, to swing back in behind Labour before the next election.
Starmer's part of the bargain is to hammer the left inside Labour and tear up existing LP policy commitments on the nationalisation of certain industries, to end their plans to scrap various 'reforms' (market-driven) to the economy (though they will be allowed to talk up a 'green economy'...a watered down version of the vision as previously adopted), to soft pedal on extending trade union rights, roll back commitments to freeze retirement age for state pensions, commit to a tweaked universal credit, ditch commitments to end charitable status for rich independent schools etc etc.