In Vegas the resort fee is per room. But it does not include parking. In that case though, parking isn't as plentiful so it's no surprise they charge for parking. And the parking fee is a relatively new one. Disney has plenty of space so charging for parking doesn't seem necessary in most places. If they wanted to charge at the resorts close to the parks given the fact that people in the past took advantage in these areas, that might make sense. Or they could just charge at the resorts for day visitors.
I'm wondering if people would feel differently if they gave free parking to people who purchase packages. Just a thought.