Whole per head our GDP may be ok, it is not actually distributed that way.
Things have gone wrong since the late 1970s. A big part of that is the deregulation of banking meaning wealth has exploded in a minority of the population. Incentives to invest in manufacturing and innovation are not there as money is to be made in financial services.
Money is made by making up dubious lending schemes at the expense of investment and public services.
Look at the NHS as an example. The NHS is spending billions servicing PFIs. Invented by the Tories, exploited by New Labour. People are decried as “socialist” for wanting a more simple funding model.
The same in the railways. They’ve created bizarre funding models where millions (perhaps billions) is borrowed to fund train stock. So millions of pounds in interest is drained out to the private sector.
Local authorities are falling victim to similar schemes as their traditional funding is cut.
So the government will say “we are investing in the public sector” and we don’t see the results because it’s being paid out again in interest.
That is the problem with our economy. It has been mortgaged to the hilt. There’s no money left to pay decent wages as we owe the bankers too much.