As someone who goes to Italy yearly with a family of 4 and a dog often the smaller car storage notes are bullshit.

We rent to drive to our home here and then use bikes when or borrow the inlaws car but they often say 5 or 6 seater with room for 3 luggages but it often means at the expense of seats. I often travel with my daughter's stroller beneath the kids feet and a luggage or several backpacks on the floor or in the middle seat and for a several hours drive it's not comfy. Meanwhile my traverse in the states I can fit all of them plus the luggages etc on way to anywhere and we're all comfy for hours.

Not that that's a justification for larger cars but it's definitely not on par and you totally need to play Tetris or sacrifice comfort to make it work.