Everything is getting harder and harder for the average bloke, but now even the independent mechanics are struggling more than ever to work on new cars. Manufacturers have component protection software for many of their control units/modules, so even if you can diagnose a fault, you cannot simply plug-and-play to repair.
It has been the case where a lot of modules need to be coded in, but with component protection software so advanced, a part will require an access code punched in to activate the module. This code can only be retrieved via the manufacturer using their diagnostic software after an online submission is made.
You can also forget about using second hand parts from the wrecker! With component protection software the module is programmed to one VIN and one VIN only. It cannot be reprogrammed to another vehicle; it's locked to the original car it was programmed to.
CAN Bus is a PITA but now it will be a lot worse.