>one thing people who don't own one seem to not know this isn't as simple as a paper printer. Jamming happens, getting the thing to stick to the plate can be a nightmare, changing hotends is a thing and currently no way plug and play, and so on

Sooo... all the same sorta shit when normal printers were introduced? The process will be simplified. Quality will improve. Everything will get easier in time.

Programmable matter... interesting, but you will most certainly have far more friction points getting that workable and simple to use, without the sorta issues you raise. 3D printing just seems far more viable to me and can already create all sorts of end products, especially at industrial scale with metals and all. Even talking about building say a computer, I see 3D printing + robotics being the better path. No way programmable matter is gonna be doing that within the next 100+ years, while I believe it's not far away at all with 3D printing and robotics. Hell, 3D printing already does circuit boards and such.