What you say! You are correct in that I have a lot to learn in 3D printing. But I have actually printed a total of 3 objects so far, all were at 200 thickness with an Ultimaker original. The objects look like a bit crude if functional prototypes, nothing like the high resolution test prints you can see on certain review sites. Grain and layers are clearly visible. Especially on curved surfaces you can see separate individual strings of material. (The printer is a bit off the best settings, so there are some artifacts/defects too.)

So we get to the point where the stated specs are almost meaningless, and in reality it depends a lot on the generation/specs of the filament and the quality of the printer's mechanics and whether they are designed for high speed printing (acceleration etc).

Also you'd expect printers to eventually specialize in fine resolution vs fast printing. So the width of the printed thread is dependent strictly on the nozzle diameter and we can't just push material through faster/longer to make it wider? But somehow we can manipulate layer thickness still... It sounds like each printer is pretty fixed in the speed/quality it can print.

Is there currently much selection in nozzle diameter for consumer devices? Does it make sense to change between arbitrary diameter eg. via a quick change system like on newer Ultimakers? I mean would there be issues with filament feeding or other parts of the moving print head - obviously travel speeds etc could be an issue with fine&fast printing if the printer is not designed and built with that in mind.

About multiple printers, I thought so 3D printing would seem to parallelize well because you'd want to break large important objects into several components and also the waiting time can be used for 3D design or whatever. You shouldn't rush it though, unless you're a professional of course, since if you buy a new printer whenever there is new technology, lower price, higher speed, better quality, nicer features etc, you'll add one more to unit capacity every year anyway

Thanks for the wonderful replies!