I don't believe in the "you can't work on cars yourself anymore" saying. You plug an obd2 scanner in and it practically tells you exactly what needs replaced.
As far as actually doing the work. Yes, engine bays have gotten more tightly packed, but replacing parts still only require 2 things, loosening and tightening. I think things have actually become easier.
Replacing brake pads and rotors are a lot easier than replacing drums and shoes.
Replacing spark plugs and wires/coils are a lot easier. With overhead cams, everything sits right there on top of the engine. Spark plug wires and coils are now combined into one thing. You don't have to worry about timing lights and all that bullshit either.
Carburetor? Fuck that noise, you can replace a fuel injector in 5 mins.
Not to mention that cars have become 100x more reliable than what they used to be. Besides basic maintenance, usually if anything breaks it's just a quick sensor replacement.