Many, if not most of the liveaboards have jobs, or a highly portable and in-demand trade, like my friend. Some of them have pretty upscale jobs, especially in the Bay area. I knew one who was the manager of an engineering departtment for a well-known international corporation. A few are pensioners or independently wealthy or living off savings. A very few are true wanderers, stopping to work only when they run low on cash. This is particularly true of many of the blue water voyagers, people who are undertaking a circumnvigation, people who are famous for their resourcefulness and adaptability. But most just happen to prefer the liveaboard lifestlyle. You can't maintain a sailboat for very long as a vagabond, not just the physical maintenance, but all the docking fees etc run up pretty quick.

I remember in Sausalito they were trying to tax them out of existence,
by declaring their boats as "landfill". Obviously, some people simply cannot stand to see these folks living independently of the system. Maybe it just reminds them of the conessions and compromises they've had to make in their own lives.