Get a bag. My family have two cars. We have two kids. Somehow we manage to do all stuff you are moaning about using a bag. I think your argument boils down to

Get a bag. My family have two cars. We have two kids. Somehow we manage to do all stuff you are moaning about using a bag. I think your argument boils down to how much effort are you willing to do to save some cash. For you storing a few books in the car is worth $500 a year to you. For most of us we'd take that $500 and buy a bag. I'm sure if we're all sharing cars you'll be able to order one with a child seat. And why wouldn't they have complimentary wet wipes and all the other stuff? Books, iPad, whatever.