In the article they say they are offering London salaries. Fine. But Cardiff is not the same as London ! London is huge comapred to Cardiff. Cardiff has about 500,000 people in its urban area compared to 10,000,000 in London, and Cardiff is about 30 square miles compared to almost 700 square miles for London [1]. As such London just has a lot more going on - theatre, museums, nightlife, restaurants, sports, shopping,…
Or this is the same kind on insanity that you see with the Bay Area? Or hell, even Vancouver.
Everyone's rushing there for the same reason, with all the cultural things that's suppose to be going on in the big city, only to find that the high CoL make life actually quite a bit more difficult to enjoy.
It gentrifies the area quickly, the commute is either long (in the case of the bay area) or being one of the sardine in the Tube.
The disposable income ends up being lower, so there's less money to actually enjoy the things that actually attracted people to the cities.