Ah, I get it now. The "devil you know" argument. In other contexts, that does have its merits. In the context of Brexit, however, it amounts to saying: "Well, I clearly voted against setting the house on fire. But now that it's burning, I oppose any effort to put out the flames because I'm afraid of getting wet stains on the couch."

Seconding this. For anyone interested in wider discussion of the difference in attitude between whether it was a mistake at the time, vs what we should do now, this was discussed in more detail on the opinion brief podcast by the polling org more in common.

Direct podcast link. Brexit discussion starts at 34:31 and ends at 1:01:43.

Some notes:

• Support for the status quo when it comes to our relationship with the EU is highly correlated with how the economy is doing
  • When we were in the EU, support for membership was high when the economy was doing well, and low when the economy was doing badly
  • Now that we are out, it's flipped: support for membership is lower when the economy is doing better, and higher when the economy is doing badly
• There's a similar correlation between how insecure the world feels / how scared the public feels and our positive attitudes towards membership of the EU
• Rejoin / stay out is ~2:1 in favour of rejoin. However, this probably wouldn't be robust if another referendum actually happened:
  • "applicant status is supplicant status". By rejoining, EU would give a list of requirements and then say "call us once these are done".
  • It's very one-sided, would make the leaving process look like a battle between equals in comparison
  • This would be quite politically toxic. So, public opinion would likely shift in a sceptical direction in any debate.
  • This eurosceptic shift is seen in most countries that join the EU, so you need a massive level of support to begin with
• Although the UK could use the same Euro trick as Poland and Sweden, where they say: "yes, we'll definitely take the Euro at some point, just not for the forseeable future", this argument could only come after the negotiations - everyone would have to pretend that we're really serious about taking the Euro while negotiating, which would be politically toxic
• No politician is going to start negotiations with the EU. Negotiations take 5+ years - any significant economic benefits would come after 10+ years. In the meantime you cost yourself significant political capital pushing it through

Some other interesting discussions:

• Rise in populist parties is because UK politicians no longer have an easy group to blame whatever goes wrong on. UK voters are voting against the status quo as a protest vote because they're still unhappy
• Leave campaign's success came from tying membership in the EU (which no-one really cared about) to immigration (which many voters cared about). Now, that same tying of immigration to a relatively settled topic on the right is happening with the ECHR
  • If we leave the ECHR, we effectively get a no deal brexit. The EU would be at liberty to rip up all our trading agreements, because they're contingent on membership of the ECHR
• The Remain campaign really badly interpreted the results from the Scottish referendum. Yes, they won the referendum, but during the process, support for leaving the UK went from 25% to 45%. Euroscepticism started almost neck-and-neck before the referendum campaigning began