It's standard usage to call Keynsianism a governing philosophy. Here are Backhouse and Bateman in the New Palgrave Dictionary of Economics noting that it can refer to a political philosophy or, more narrowly, to an approach to macroeconomic management. It’s a bit odd you don’t know this.
Britain's university system, built in large part after WW2, was one of most important elements in a state project to modernise the UK economy. From Thatcher onwards successive governments have tried out various kinds of market-mimicking governance and now the sector seems to be in full-blown crisis.
To be clear, Keynesianism and Thatcherism are both modes for managing a mixed economy - philosophies of government, as I say. But they are different, quite distinct, modes. Thatcherism is extant, and it informs 4/5 major political parties in the UK.
My view is Thatcherism is a particular approach to moral and political economy, which replaced Keynesianism, and which is still the governing philosophy of 4/5 parties in OP. I don't see why you find this so hard to understand.
Et tu, Bab
They will be as loudly and confidently wrong in future as they have been in the past: they have no incentive to change, and I am afraid their foolish fans will love them for it. Because the message is always, you're OK, the world is as it should be, and what you feel is true, is true.
The chart you posted shows that UK has higher levels of state expenditure now than in the 1960s. It doesn't show that we're a normal country in terms of state regulation/intervention. But you haven't answered the question, does 79 mark a break with 45 or not? If it does, when did we replace it?
No one is saying that 2026 is the same as 1986, or that Thatcher is telling Starmer what to do from the other side. Do you think Thatcher established a different model of political and moral economy in the UK after 1979? Has that model been replaced since then? What new model has replaced it?