The 2019 GE result was a total rejection of what was considered to be a Labour Party led by a perceived left wing Corbyn.
Recent by-election results and opinion polls show a rejection of what many consider to be a right wing Tory Party.
I am not a great fan of the oh so bland, fence-sitting Starmer but could it be that, at heart, this country is politically middle of the road and he understands this and is quite prepared to take the criticism of those on the left of the Labour Party in the short term in order to actually look for Tory convert votes as well as the more centrist Labour supporters?
Not exciting at all (but look what excitement of the elections of Blair and Johnson led to), and an anathema to those who want a politician who is permanently protesting loudly even if they cannot get into a position to actually change things. The most important responsibility of an opposition leader is not to oppose as loudly as they can but to get into a position where they can effect change by defeating the sitting government.
So far that part of the job seems to be working, but it is only half the story, and the real judgement of Starmer (hopefully) should come after a few years of a Labour government.