This is on topic. You're just throwing out superlatives: "massively", "spectacularly". Nothing remotely quantifiable or even justifiable by relative comparisons.
Yeah, sure, the UK is 10 percent poorer now because of brexit, better?
Haiti is a massively or spectacularly failed nation. The UK is not. Among "its peers" it ranks well in absolute GDP and per capita GDP. "Failure" isn't on any list of remotely non-risible descriptions.
The UK is massively underperforming it's peers in the EU post Brexit. The UK was matching their peers in the EU pre brexit.
That's a failure. Not a failed nation, but a failure in economic performance. And the point of divergence, surprise, Brexit.
And my contention is that departing the EU was an effect of dissatisfaction. PM churn started before Brexit, which makes Brexit a poor candidate for your claims about dissatisfaction.
The PM churn absolutely did not start before brexit.
Margaret Thatcher: 11 years, 211 days
Tony Blair: 10 years, 58 days
John Major: 6 years, 157 days
David Cameron: 6 years, 65 days
*Boris Johnson: 3 years, 45 days
*Theresa May: 3 years, 11 days
*Gordon Brown: 2 years, 319 days
*Rishi Sunak: 1 year, 254 days
*Keir Starmer: 1 year, 353 days
(Ongoing)
*Liz Truss: 0 years, 49 days
*Post Brexit Prime Ministers.
The UK had relatively stable governments before brexit, not a single PM has served a full term since.