As someone who works on cars and motorcycles as a hobby, I'd say yes and no.
1. Plugging into your car to find out where the faults are is fantastic. Emission laws have resulted in cars being much more complex. With all of the sensors all over the vehicle (MAF, MAP, O2, CPS, ABS, etc.) it's great having a computer tell you which one is sending voltage outside parameters. If there was no computer telling you where the problem was you'd spend quite a bit of time with a multimeter.
2. When someone says that something is harder on a new car than an old car, sometimes that's true. Smaller bodies, different collision requirements, etc. all result in less room. On the other hand, a ton of stuff is modular and easily swapped out. In fact, it's easier to swap out than in the past. The problem is, the swapping out is much more specific to the vehicle and manufacturer. If you aren't familiar with the car, it can be quite a pain. But...
3. Just about everything is on the internet these days. There's a video step-by-step for just about any procedure on any car. That's something you didn't have back in the day (although I suppose it was less necessary).