yr right - I for one, also love the KISS principle. Unfortunately for us dinosaurs, substantial amounts of electronics that control a wide range of engine control inputs are here to stay.
If it wasn't for modern electronics, engines would still be relying on very imprecise engine fuelling setups, imprecise and less reliable ignition systems, and an inability to adjust a wide range of other important combustion controllers.
The main problems with electronics come with the "cheapest arrangement we can purchase" mentality, and the lack of knowledge of actual operating conditions by engine designers which results in poor positioning of electronics, and less-than-ideal-design wiring connectors and wiring harnesses.
Electronic components often have a huge profit margin in their selling price that is designed to recoup design and research costs.
If competition via aftermarket manufacturers is introduced, prices rapidly fall to realistic levels.
Unfortunately, aviation is still full of the "captive customer" or "captive market" production principle, that ensures high costs for owners.