> would massively simplify iteration

I seriously doubt it.

It’s far easier and more effective (and economical) to have a bunch of jelly bean components around in stock.

You’re going to have a hard time 3D printing anything that can be solderable (either the 3D printer needs to work at high temperatures for DIY, or you need exotic solder that melts at low temperatures).

If you have the need to fabricate quick PCBs for prototyping, you’ll be better served by a cheap CNC machine and some copper foil blanks.

The only real promise I see is that you might, in the very long future, be able to print custom multi-purpose devices, that integrate the characteristics of non critical electronics with mechanical elements, i.e. integrating NTCs on cases or fan supports,..