The UK isn't as big as those places you've mentioned, it isn't that national rules the roost, just that more of the news that is happening fits better in national news or I should probably say more of the news that is of interest to most people.
I think it's time to bust this size myth once and for all.
Only two "markets" in the US, New York and Los Angeles, are bigger than the London region here in the UK.
Of the 200+ markets in the US, over 150 of them, are smaller than the old South West/Westcountry region, and one is even smaller than Channel Television.
In Canada, a country with just under half our population, there are 43 TV markets, again most of which are smaller than the South West/Westcountry.
It's all to do with attitude towards regional television, and nothing at all to do with size.
Myth BUSTED!