“if people have changed their minds, why would their opinion count for less now than it did in June?“
Because nothing much has changed (as far as the question of UK’s EU membership goes) to justify asking the question again.
“They are at the very least a lot better informed now.”
How so? They were fed a load of exaggerations, half-truths and lies (by both sides) prior to June 23rd and have been fed similar garbage since. The things that have been measured since then largely show little or no change (as would be expected), with the exception of the Pound’s devaluation (which was necessary anyway, regardless of the vote). Many things forecast under “Project Fear” (emergency budget, tax rises, collapse of inward investment, stock market crash, financial instability, large companies upping sticks) have not, thusfar, reared their head (as also would be expected). I’m not saying they will not, but they haven’t so far – certainly not sufficiently to cause people to regret voting to leave and certainly not enough to make them “better informed”.
“…maybe a 55-60% vote required to overturn the status quo, on the basis that the status quo also had public opinion behind it.”
Two things wrong with that, jno: (1) Why assume that the status quo has public support? And (2) remaining in the EU does not involve a “status quo”. The EU has changed beyond recognition in the last 40 years (one of the main reasons many people called for a referendum - they were reasonably happy with the EEC but not with the EU) and will change further beyond recognition in the next 20.