I had, for years, the same question as Agathon.

Having friend with 3d printers, I never had the need to ask them for anything 3d printed. Only recently I needed a coupling for a hand blender, found the 3d model online for free, had it printed in ABS and works perfectly.

Now there are a lot more interesting and stronger material filaments available and could be used in industrial machinery. Where the design is no longer limited to what can be milled/turned. And yo can have them quickly and a lot cheaper than CNCed for small runs.

But for those materials you need a high temperature heated chamber and there is a patent (still) for the heated chamber so the few printers on the market have prices above 40-50k €

I just started to design such a 3d printer and it is not easy to have everything except the hotend built around a 250 degC oven without leaking too much heat... :)