Polling showed that Labour's 2017 manifesto was very popular. A majority support re-nationalisation of the railways and utilities and they trust Labour more with the NHS. I'm an incurable optimist and I can envisage a more caring, socialistic society emerging from this crisis. A 1945 moment.
Maybe.
Polling showed individual commitments in their manifesto were popular, when put to the public as individual questions. The most significant poll (and the only one that matters) showed that collectively they weren't as popular as what was on offer from Theresa May after one of the worst run political campaigns in modern history! And I would imagine that we'd agree that May's manifesto wasn't all that popular.
When asked "Do you support the nationalisation of the railways?" by a pollster, it's easy for that question to garner support. In context, when asked whether people support nationalising the railways, and the utilities, and increasing spending on childcare, the NHS, ending tuition fees, which would mean putting taxes up for individuals and businesses, and not paying off any national debt, people come up with a very different answer (and always have).
I just don't see the evidence - putting the rights and wrongs of the policies to one side - that the public has had a wholesale change of mood. Which is why, if I was of a left leaning persuasion, I'd be fully supportive of a slightly more moderate position, which I think Starmer can deliver.
Perhaps, however, I'm too cynical and your optimism will win the day. It's fantastic to be an optimist, and much needed when following the R's
Edit - I guess I'm a pragmatist to my core, and as much as anything, this is also a question of pragmatism vs principle; which often also shapes how one sees the future. Plus, I was wrong about the results for Trump, Brexit, 2017, and 2015, so I'm [slowly] learning not to make predictions with any certainty...