I think the relevant question is, why did a Thatcherite monetary policy collapse overnight in 2022 when it didn't in the early 1980s?

One reason is that the British nationalized services that Thatcher sold off to private investors in the 1980s (railroads, electricity, etc.) no longer exist, other than the national health service, which the British public would riot over if it was privatized. With nothing left to cannibalize, there was no way for the government to boost the financial markets, leading to the collapse of the pound.

This is good news, as it signals that the era of neoliberalism, with all its intellectual hypocrisy and disastrous outcomes, is suffering one death blow after another, and will finally be discarded on the dustbin of history once and for all.