Self sufficient seastead
There are people who would like to have a self sufficient seastead. A Single Family Seastead with a few extras should be able to serve this part of the seastead market.
Contents
Food
A seasteader could get their own food by fishing, hydroponics, storage, and maybe aquaculture. A seastead should act as a Fish Aggregating Device so it will probably be easy to catch plenty of fish for one family. Watermakers are easy enough. A supply of hydroponics nutrients to last many years is not very large (most of the mass of food comes from water and the carbon in the air). Food storage food is also very reasonably priced and small enough to fit on a seastead.
Power
Solar panels can provide power for 25+ years. Costs are now down to around $2/watt. Could have a very small generator as a backup.
Propulsion
Solar would be enough power for electric thrusters if we use efficient propellers. Might also use a kite and sea-anchor. You can get a 500 lbs thruster that uses about 2,000 watts. If you only drove when the sun was up and used $2/watt panels, that is about $4,000 worth of solar panels. Probably you want batteries and several times that in solar panels.
Market size
It is not clear large this market is, but even a small market segment could help with initial sales of seasteads.
Conclusions
A seastead can be a great platform for a self sufficient life.