Also, outlet/switch boxes get nailed to the studs during construction, and modifications to those boxes are fastened to the drywall, in my experience.
You can either train more workers to do it the old way or invent new ways that require fewer workers (or less highly-skilled ones).
Kind of how PEX plumbing (whatever its drawbacks) has made it much simpler to plumb a house than it was when soldering copper fittings onto copper pipes was the norm (let alone threaded connections shudder).
Then again, wire nuts aren't that great either.
It could even start out as basically a fancy wire stripper and a box with push-in connections that switches/outlets subsequently plug into.
Also the only way to replace the outlet would seem to be to rip out the entire wall and splice in new cables like a complete do-over which seems a bit extreme although profitable, or do a high resistance fire causing re-crimp. This is "OK" for receptacles that last the life of the house, if the life of the house is short enough, but wall switches would be essentially unreplacable.
One idea that might save money is giving up on copper switched wall switches. Feed the wall switch 12 volts and let them speak zwave to control things.
The boxes would come in a few varieties based on the number of cables that could pass into/through them. Again I'm picturing some kind of intermediate layer between the box and the device that could accommodate less-common connection arrangements, but maybe you lose a bit of flexibility in the name of progress.
The connections wouldn't have to be 100% reliable, but at least as reliable than hand-twisted wires and wire nuts (also AFCI breakers could eliminate a lot of the fire risk).
(edited, not to say its impossible; perhaps your innovation would in itself be the world first reliable connector...)
Right now you have to fasten a box to the wall structure, cut the wire so that about 8" can make its way into the box, strip the outer insulation and insert it into the box, strip at least some of the individual conductors, and then splice (by twisting and using wire nuts, or less commonly using a press-fit dingus) the ones that need to be spliced.
You then repeat that for every outlet (which in electrician-speak includes lamps and such) on the circuit. Then repeat that for every circuit. You are now ready for your "rough" electrical inspection (the one before the in-wall wiring is covered).
Then before the final inspection you have to individually connect each conductor to (usually) a screw on the actual device before cramming^H^H^H^H^H^H carefully folding the wire back into the box and screwing the device in place, followed by screwing the cover in place.
Repeat for every outlet in the unit and you are ready for your final inspection.
What I'm picturing is a special box that can insulation-displacement-crimp right onto the wire (probably with some giant pliers. On the inside it has some sockets that the eventual device plugs straight into, possibly with a sort of optional middleware layer that can reconfigure the connections for less common hookups.
So you crimp all the boxes to the wire and fasten them to the wall structure and you're ready for the rough inspection.
Then after the walls are covered you plug in the devices directly for all of the common configurations (e.g. just a receptacle in a string of receptacles) and fiddle with some kind of middle layer for the oddball configurations (e.g. a duplex receptacle where one of them is switched).
As an alternative to the "middleware" maybe there are a collection of different boxes that are pre-configured for the circuit arrangement in question (not unlike plumbing components are today).