You are confusing things. Net neutrality isn't about what tier of service you have. It is about ensuring that you aren't getting purposefully manipulated speed for the tier you have. Let's use your examples since you seem to understand those...
Do you think everyone needs the same speed? Does your grandmother need the same speed as an MIT researcher?
Do you think the MIT researcher should pay for the higher tier and be slowed down to Grandma's speed for some sites?
Same priciple for package delivery. Do you think everyone needs their package overnight? Or are there different needs.
Do you think your overnight package should be 3 days to certain destinations for the same price of overnight delivery?
Same principle for travel. Do you think everyone needs a supersonic transport, or are some fine with taking a Greyhound.
Do you think those that pay for the supersonic speed should be shuttled to the Grayhound station for certain destinations because that destination didn't pay the airlines for it?