The currency has not collapsed. The exchange rate is very similar to that in 2013. Shall we blame the EU and euro for 2013 as we were enthusiastic members back then?
I think you make a good point. There is a tendency to blame every negative effect on Brexit, as if all were sweetness before the vote, and all is crap afterwards. It's not correct but it's going to happen.
Some prime examples. The IFS study reported as fact the fall in real wages post 2008-2013, but that was largely ignored and instead people focused on the difference between their 2021 forecast pre and post Brexit. Greece is still in tatters and has been since 2008. The Italian banking system remains on life support and could expire at any moment. RBS is still in the sh*t and has been since 2008.
But nope, all was going fine before the referendum. Honest.