China Mieville, author of some of the most beautifully written, cruelest speculative fiction ever in print, wrote a piece back in September about ships as cities/nations. It's both a discussion of the nature of utopias and an interesting anti-libertarianist statement.
Floating cities are dreamed of because how cool is that?—an entirely legitimate, admirable reason. The archives of seasteading are irresistible reading, the best of the utopias are awesome, and floating-city imaginings are in themselves a delightful mental game. The problem is the crippling of this tradition by free-market vulgarians.
In these times, utopian imagination for its own sake has a bad rap, so some unconvincing instrumental rationale must be tacked on—yeah, save the planet, whatever. Among the rather cautious purposes architect Eugene Tsui lists for his proposed floating city of Nexus are the development of mariculture, clean energy and “experimental education programs”: Reading these bullet points, one might almost forget that Nexus is a five-mile-long, self-propelling mountainous island shaped like a horseshoe crab. Its sheer beautiful preposterousness shouldn’t be an embarrassment: It is the point of the dream, whatever the design specs say.