Care to specify which older cars, or at least how old they are? Pre-emissions (i.e. 1960's) you may have a point. At least your basic cars were bog simple, and the old Detroit iron was such overkill that you really didn't care if a cylinder or two wasn't working. They also needed more maintenance and handled like pigs. Then somebody decided that opaque city air was a bad idea. 70's emissions compliant cars were such insane nightmares of vacuum tubing that you couldn't see the engine. Ever try to trace down a leak in a vacuum system? Then there was that nightmare of things that controlled or were controlled by the vacuum system. It was basically a cobbled together mechanical computer.
The best thing to ever happened to cars was fuel injection and ECU's. Later they used computer control for those decadent automatic transmissions and that was a good idea. They also vastly increased tire life, made spark plugs that lasted over 100k miles, and all kinds of other stuff to reduce maintenance. The problem is that, especially in the last ten years, they've introduced all sort of unnecessary crap that kills the reliability and increases maintenance costs. How many networked unnecessary electronic boxes do you need? I want the engine and the tranny to run, and screw everything else. Power sliding doors on mini-vans? I cursed it and predicted it would be a problem when my wife bought her 2006 Sienna. The chickens have now come home to roost and the one good thing is I think I can completely disable the power crap by cutting a cable. Imagine people having to use their hands? Power seats? Unless you have a physical handicap you should be able to adjust your seat position without electro-mechanical assistance!. No really, I've heard old-timers talk about it.