Well, just as an example: You don't make anything out of fiberglass. You get glass matte cloth or roving and resin and then you mold your shape, and what results is fiberglass. Both the glass fiber and resin are industrial products machine created and distributed by a highly complex system. It is also a highly skilled operation, not just anyone can do it. The mold is usually made out of glass too, and it is formed on a plug built up from plywood. It's all part of a big industrial operation with skilled craftsmen and machine made products and devices at every step. If you had a warehouse full of materials and a boatyard full of workers you could probably build boats without power tools, but how would you feed them and their families until you found a market for your vessels? And there would be no market for powerboats, you'd have to build sailers, so you'd need sailcloth and sailmakers, line,

Going back in technology doesn't necessarily mean simpler. A clipper ship is much less complex than a steam ship, but the number of human skills needed to design, build, maintain and sail her far exceed those required to operate a steam vessel. I consider myself a decent sailor, but I don't think I could teach myself to operate a square-rigger, much less train a crew of lubbers to help me.

Technology tends to disperse the human skills needed for its own maintenance, and earlier
(simpler) technologies wither because no one is trained to carry them out any more. Think of it another away, thirty years ago, almost any man could tune up his own car. Today, maybe one man in a thousand knows how to saddle a horse. How many know how to make saddles? How many know how to tan saddle leather, how many know how to raise cattle for leather? And that's a job that needs to be done from horseback! All those links and connections are gone with the wind.