It's not.
I have a couple of 60s Mustangs and several newer cars. My original '65 needs ignition service (what most people call a "tune up") every couple of years (of very modest usage). My '66, converted to electronic ignition, gets about twice as long (and 10x as many miles) before needing ignition service. They both end up fouling plugs because of the terrible mixture control and distribution inherent in their carbureted designs.
My wife's 2005 Honda CR-V gets about 100K to a set of plugs. (Fuel injection, closed loop mixture control, and electronic ignition are the key enhancements that enable this long a time between tune-ups.)
My diesel Mercedes and Nissan LEAF obviously never get tune ups.
You don't do valve adjustments on the Mercedes?
About the only thing I've done abnormal on the car in 7 years is replace two glow plugs. (And when the second one went, I actually replaced the 5 that hadn't been changed yet, since they are cheap and I didn't want to take the manifold off again to change #3...)
For even lower maintenance look at electric cars. I think Tesla has very very low maintenance requirements for the first years.