Oh it can be. Luckily the use of steel fish tape or fiberglass fish rods

[Bruno1949]

help but outside walls with insulation and plaster and lath walls can get very very tight! I’ve had to fight for an hour and not get anywhere and then one last try gets it on the first attempt. I’ve also had to actually cut one of the boxes out of the wall because of obstructions or just having crappy boxes installed. It’s rare but each situation is different. I try to avoid opening the walls, it just takes too much time to fix, but sometimes it has to happen.