The first seasteads will operate under the same maritime laws as existing ships... Although [cruise] companies have major operations within U.S. territorial waters, the U.S. does not interfere very much with their operations. This is due, in part, to the fact that cruise lines bring in jobs and revenue to the U.S. economy. If the U.S. were to try to interfere too much, the cruise lines would simply move their operations elsewhere. Similarly, seasteads will trade extensively with land-based businesses. The people who profit from those relationships will encourage their government not to interfere and drive away the seasteads business.
LOL That's classic. Because the economic bolstering of doing business with a community of a couple thousand people (at most) definitely outweighs the advantage of simply blockading food from the community and then seizing all the assets.
There's a lot of assets to gain from invading Switzerland too, it doesn't stop small countries from existing. What if the couple of thousand people pay taxes for defense, making the cost of invasion outweigh the assets?
The question of whether these artificial islands will get invaded seems to me to depend on:
1. The economies of scale in defense. Which I'm unsure about.
2. The political cost of invasion. America could invade Canada pretty easily, and probably profit from seizing it's assets, but it wouldn't be politically popular. Perhaps there could be a similar relationship if people, including both the general population and rich billionaires, are supportive of these islands off the coast of the US.
The fact that there isn't an obvious answer makes the experiment all the more interesting.