loefet said:
The only park I find strange on that list is Hakkejima Sea Paradise
There's no entrance fee though. A lot of people use it as a recreation ground, a place to take a walk next to the sea, hang out with friends for coffee/drinks at the waterfront bars. I'm guessing these people must be included in those figures.
Plus, the animal shows and attractions are the biggest draw there. It's not about the rides for the vast majority of visitors. When I was there, the rides were all walk-on, but the dolphin/whale show and various aquaria were packed.
It's really not the middle of nowhere either. Yokohama has a population approaching 4 million, that's before the 12 million in Tokyo who could potentially get there in under an hour.