Car seat/carrier

Anyone else think it's odd no one has come up with an easier invention of the car seat/carrier? I just would think there would be an easier way lugging your child around without it being heavy or inconvenient. Yes, I can take my child IN and OUT of the car seat to put them in a stroller or body wrap but that's annoying when you are making quick trips. I know they have the car seat carrier that turns into a stroller which is the easiest idea I've seen but it has some flaws and is way too expensive. Every pediatrician appointment, I see moms lugging their heavy carrier around and it just blows my mind there is no easier way.