Well he to take a look at a map and consider the differences in geography and demographics. It's pretty easy to have good wireless coverage in densely-populated postage-stamp sized countries, especially when not encumbered by zoning ("you are NOT going to put that tower where I can see it!").
It is also advisable to consider geography. Japan is no slouch when it comes to wireless, yet there are numerous dead zones in big cities. Any honest coverage map of Japan will show that there is no coverage at all in the sparsely-populated mountainous interior of Japan; the coverage is in the big cities which are all on the coasts. I know from personal experience that you lose service as soon as you get a few kilometers from the urban core.
I also know from personal experience that there are numerous dead zones in London.
Now, if two relatively small island nations have problems, consider wireless coverage issues in a large continental nation, and you have the situation faced by Canada, the US, and Mexico.
-- Mark --