We can’t get parts for my wife’s 7 year old Buick convertible anymore so that’s not really true. We took it to the dealer to get a service done and they broke her fob then messed around for two weeks before declaring that they couldn’t source a replacement. So it depends greatly on the vehicle. If it isn’t an American truck then good luck getting documentation or parts for it. Luckily our regular mechanic actually knows what he’s doing so he’s able to come up with alternatives for things like turbo solenoids. But the OEM parts are always on backorder and are 10x as expensive.

I've heard of year+ backorders on parts for ~5 year old models recently. High volume slightly older cars like a 2015 corolla sometimes even have backorders despite how many are still driving

You might want to take a closer look into the current state of play on new and late model vehicle parts availability and general serviceability, because your take here appears to be a couple decades out of date. Parts are frequently difficult or impossible to source for cars that are less than 5 years old.