This is not the typical case of "been in power too long". BIPTL is when a ruling party has been in control long enough they get the blame for the low level friction in every society. This is why so many sensible Britains were willing to leave the EU.
The problem Tories face is a self inflicted wound which is infected because the patient left the hospital, against medical advice. Brexit was and still is a stupid idea. It was put forward by people who thought it would lead to personal gain, either political or financial, and was supported by people who didn't understand what it meant.
It was sold using the trickle down pitch. Just say something that is grammatically correct and vaguely plausible. "We must take control of our borders" is always good. It's strong and uses all the right words.
Unfortunately for Tories, the EU was a good idea and it worked. It wasn't perfect, but it was so good, it can't be improved upon. When it comes time for the benefits to magically trickle down, the potting soil is bone dry and the petunias are wilting.
The situation Britain faces today is grim because the best case scenario is scraping "barely good enough". It can get worse. There's a penalty to be paid for putting stupid people in charge of important things and bill has come due.
I don't think there is much disagreement here. I concede on BIPTL's meaning from the trademarked sense where people just vote "for a change" because people are stupid.
I was speaking more to the generalized, they've been in power, enacted their policies and their policies suck... and the results of those policies have been more immediately forth coming than on average, and they have little recourse here. Vote for us... we'll keep doing the same stuff that is failing the country. Truss effectively was fired because Tory policy made the markets panic, not her policies, Tory policies.