You need fresh water and the cheap way to get is is from land, so you need land infra anyway, you also need food and you can't produce it locally, yes you can fish, but you do not live well ONLY on fish and some algae... Beside that logistics is a nightmare.
Long story short: FEW can live, perhaps even very well for some of them, on boats, but only if most others do not. That's an important issue too many forget even when they speak about Green New Deal: yes, we live in homes. We might WFH. BUT we also need factories, hospitals, schools, they are mandatory to live well and they need to be counted in the game: we need to sustain them as well. We need workers and they need a life as well. That's not much "housing problem" but is tied because we need a home to live BUT we also need to be physically nearby something else to do so as well. The dream of an autonomous home is not much different than the dream of an autonomous house-boat or starship or house-truck, house-airplane etc we can made "relatively autonomous" homes, tucks, ships, airplanes, ... where relatively means "you are free to live in in comfort FOR A LIMITED PERIOD OF TIME until something breaks, for instance, and such "things" can exists for you just because there is a complex industrial and social system behind. We still miss the 3D printer able to print itself...
That's the real issue... We are able to reproduce ourselves only with our body (well, if we can keep alive in nature) but we can't do the same for anything we build...