The avg person wouldn't be able to fix your jeep when it's broke down. As stated earlier, not being able to fix a new vehicle has to do with ignorance. Not difficulty.
Ignorance is part of it but so is difficulty. My mechanical skills are limited but I have a few friends that skills as to most of us. Between them, You Tube and myself we can get allot done, esp on the older vehicles.
We have limitations, esp with electronics and wiring on new vehicles. My wonderful cushy Acadia Denali has more electronics in the drives seat with the adjustment, heater and AC then my entire old truck. My old truck is almost 40 years old and going strong as are many old trucks. We will see how many of todays trucks are on the road 40 years from now. There are so many different "systems" in new vehicles that I just don't see all these parts sitting down at the parts store or in some farmers field decades from now, this is were the difficulty will be. Even the difficulty figuring out what needs to be replaced and then replacing it will be more difficult. Here is a 5 minute video showing how to replace the battery in my Acadia.
https://www.google.com/search?sourc...1.31.2453...0j0i131k1.0.v4UtlAnTxL8#kpvalbx=1
On my kids 2004, not ever that new, cavalier you have to take of a heat shield and loosen the exhaust manifold to replace the thermostat or reaching around then go over and under this and that to loosen the bolts to get to the thermostat. On my older vehicles it is right up front.