Stuff like changing cabin air filter or your own oil takes no additional space beyond the space already occupied by the parked car. You don't even need to lift the car to change the oil in most cases unless the car designers were massochists. Sure, maybe not everyone can get down on their back anymore, but that shouldn't be an issue for able bodied people.
Doing your own oil changes is not worth the hassle when considering the risk of a spill and the difficulty of legal disposal—unless you have a fancy engine that needs frequent oil changes.
Cabin air filter and wiper fluid, sure. Headlights and taillights used to be a no-brainer, but now those are often sealed LED assemblies and difficult to access as well.