https://en.wikipedia.org/wiki/Cardiff_urban_area
Here is a map of the Cardiff urban area
It's about half the size and half the population of the Newcastle urban area
Newcastle merges South with Gateshead and then inland along the Tyne to form a densely populated area
Cardiff could be argued to merge with penarth but certainly not pontypridd and apart from the town of Caerphilly the rest of the valleys do not join Cardiff directly
To say that what people think of as " Newcastle " is twice the size of what people think as " Cardiff " is about right
Newcastle has a big arena , a bigger city centre , more night time entertainment , a big Chinatown, its bigger in every way
I would love our city and football team to have bigger crowds , be a better team , have more music venues , etc
But it just isn't as big and progressive as Leeds , Sheffield , Nottingham , Bristol etc
Just the way it is