Whilst I agree with most of your post, this assertion isn't true; a strong majority of British adults support nationalising the railways, at 64% of respondents (only 19% opposed renationalisation).
Source: https://fullfact.org/economy/do-public-want-railways-renationalised/
Do 64% of respondents actually understand what that means (and does not mean)?
"Renationalisation" is a buzzword, with little clarity on the problem it is trying to solve nor how it would solve it, ususlly used by people with a very rose-tinted view of what BR was like.