The risk-reward isn't there for pirates. Seasteads will likely be well-armed, populated, far from Somalia and other pirate operating areas, and lack the large material payload of a cargo ship or oil-tanker.
Valid point, but if I am rich enough to be living on an isolated island micro-country, and will fetch a healthy enough ransom for pirates to snatch me, I am also investing a fair amount of resources into my own defense. Think small arms, ample security systems, security guards, etc.
You don't need to board the thing to take it ransom. Just need to have a credible threat of doing serious damage. "You have 5 minutes to wire $x into our bank account or your little country gets sunk."
have some kind of contract with tugs, lifeboats, helicopter rescue, etc. You could set up some sort of insurance system for citizens/inhabitants to cover those contract retainers.
Hell, you might even end up contracting it out to the Coast Guard if they meet your needs and are close enough to count.
