Capacitors age because they are filled with liquid electrolyte, which dries out over time. Batteries age for mostly the same reason, and the chemical reaction slowly becomes irreversible. Those are easily replaceable. However, an integrated circuit is just a wafer of silicon. A piece of sand. It's going to take a long, long time for that to degrade. If it weren't for needing constant software updates and cloud connections to be useful, an iPhone could theoretically last a hundred years. "Tin whiskers" may also be a problem, but we are talking decades before you have to worry about that.

I don't think your theory about old things lasting longer because there is more mass to them is correct though. It really sounds like you are making that up because it sounds good in your head.

Why do you need performance or power efficiency in a car's computer? It just needs to go when I press the pedal, and stop when I hit the brakes. That's not complicated, and something like battery wear leveling and temperature regulation can be a completely closed system and not require any updates whatsoever.

I really don't understand why cars need so much complex stuff, I just want it to get me from A to B, ideally in comfort. My current car that's >15 years old does that just fine with no internet connection, why do I need all the complex software?