I strongly believe there was a optimal point where it was both relatively straightforward to service vehicles (or possibly easier), and their reliability was much better than what preceded them (and frankly also what came after): probably in the 90s or very early 00s. An example I would kind of think of, was GM's throttle body injection, or some of the simpler port fuel injection systems and the engine and transmission technologies concurrent with these. They have basically all of the advantages of EFI, such as behaving correctly with altitude changes, not rampantly over or under fueling the engine (because of the feedback loop with the O2 sensor, etc.), while retaining the same simplicity (or better) than their predecessors. Ignition was kind of the same way: HEI distributors, and even better, wasted spark systems, are absolutely dirt simpler, and really simpler than points and condensors, while being much more efficient and robust. The electronics on these are relatively simple, well understood (basically anyone and their bother has been able to tune and flash a lot of GM EPROMS/EEPROMS for a long time now), have replacements that are also better and open (Megasquirt and similar), and very robust.
A lot of the newer technologies, like variable valve timing, are cool, but you can still have (and did for a time) a lot of the ease of service, with much better running behavior and reliability. We can have our cake and eat it, manufacturers are just apparently very incentivized against this.