From 2018:
"there are some demographic trends that will influence opinion in future. These changes will tend to pull British public opinion in a pro-European direction, and should be sufficient to produce a majority of 52%-48% for ‘Remain’ in 2021"
https://blogs.lse.ac.uk/brexit/2018/05/01/demographic-trends...
Leave would likely win by a bigger majority if the referendum was repeated today, because the UK didn't collapse on leaving
also add the EU's disastrous vaccine procurement scheme, combined with its attempt to obscure its total incompetence with petulant nationalistic flailing
All things considered it was relatively close so not exactly a far larger chunk.
I don't have any spite towards the British people but I do hope that the EU will act in EU interest which means facilitating the return of financial services that shifted towards London since they joined and not letting the UK and whatever the borderdeal ends up as serve as a loop to ignore single market regulations.