It's pretty normal for the airport of a major city to be well outside of those major cities, given how air travel and tall buildings and large swaths of empty land for runways and population density don't exactly play well together. It's not usually that big a deal - for one thing, because you're likely to only do one leg of that journey on any given day; for another, because there's usually lots of good, tourist-friendly transit options to get from the airport to downtown.

So tourists are accustomed to this sort of thing, whereas - as pointed out above - they're not exactly accustomed to going that far out of the city while sightseeing "in the city".

I'm planning my next trip to Tokyo and got real excited reading about a Japanese computer museum (I'd love to get to play with some vintage Japanese micros, seeing how different they were from Western machines) but I don't know if I'd be willing to take three hours out of my vacation to go out to the suburbs and back...

And it takes an hour to get to Narita from Tokyo Station