I think thats a bit naive - Labour should have won in 92 against Major but they didn't probably because of Kinnock's triumphalism. Then bear in mind the Blair Govt of which Starmer became a part of - they reneged on Uni fees. So what Starmer is doing is trying not to spook the horses. The Tories are so shit and are performing so badly he basically sits back and lets them carry on fucking themselves over. The calculation is he needs to do stuff that has as little impact as possible because the Tories are so disliked they will lose big style. Doesn't matter now what numbers the Tories quote - its about how people personally feel and if they feel they are no better off then its a landslide. I hope and suspect once they win and - if its a landslide - the Labour approach will be much more radical
The Tories are also hopelessly divided (if only between those with a crumb of decency left and those without). The only time they unite is in the voting lobbies to do nasty things, or at PMQ when Sunak comes up with a weak jibe against Starmer.
I don't think it's deliberate, but flip-flopping makes him less of a moving target - except for when he's being accused of flip-flopping.
This will be the last conference before compiling the manifesto. Conference doesn't decide the manifesto like it used to, but it will give a good clue to what to expect.