You're repeating your own fallacy that there are more Superchargers in low-density areas because the low density makes it more important. That's not the case. Outside of the city Superchargers, they are mainly built to complete paths that Tesla believes its customers need or want to travel. Consider what's happened in Nebraska last year and what's happening in Wyoming this year. Tesla's is building out western I-80. Nebraska Superchargers weren't added for Nebraska. They were added to connect ot Denver (requiring 1 new Supercharger in Colorado). The new Wyoming Superchargers aren't being added for Wyoming. They are being added to connect from the Midwest to Salt Lake City and the Pacific North West. It just makes more sense to me that Tesla ramps Model 3 to high volume, address key large markets and then makes a single large effort in smaller markets. So for Iceland, add sales and a service center, and add however many Superchargers are needed to cover the island (which will be more than 3).