Sure, the sixth largest economy in the world is “poor” because too much wealth is generated by financial services in the capital and not mom and pops in small towns or whatever. That’s like saying California is poor because most of the wealth isn’t generated by McDonalds employees. You picked some romantic ideal for how money “should” be made and voila now you can complain when it isn’t so.
The article actually wants to make a point about falling living standards, but the author couldn’t resist a clickbait title so nonsensical it overshadows the rest. There’s probably some interesting analysis that could be done about UK PPS, absolute, mean and median incomes, incomes vs average cost of living etc. This is not that article.