There could be factories manufacturing your own design, just one piece. It won't be economical, but can be done. But parts are still the same - chunks and boards of wood joined together by the same few methods. Maybe some other materials thrown into the mix. With software it is similar: Different products use (mostly) the same building blocks, functions, libraries, drivers, frameworks, design patterns, ux patterns.
That is not a technical constraint and may be automated if it made sense financially. Same with software - for some time software won't be all designed, coded, tested, deployed to production without human supervision or approval. But the pieces in between are more and more filled by AI, as are the logistics of designing, manufacturing and distributing sofas.