Well, let's go with that. Let's say our universal assembler can make *anything* so any material form would be essentially free once you could conceive it. So what is scarce?

• labor (as you mentioned)
• raw materials
• land
• fresh water (in some places)

Can the assembler make food? Assume it can. You can have any food you want. But what does it make the food out of? Air? So if the assembler uses air then air is a valuable resource. Can you control air? Maybe.

Universal assemblers do not make the problems of land, water, raw materials, and labor go away. In some ways they make things worse. Who controls the land? Why would they ever give it up? What could you possibly offer that would convince someone to part with a chunk of the planet once they can turn that chunk of planet into virtually anything?

Could a universal assembler actually cause a return to feudalism? Would a universal assembler instead put a premium on the knowledge of how to assemble unique and distinct forms? Could this knowledge of how to create and invent new material forms be worth more than raw land?