Anecdata for anecdata, I've never seen 90% of big cars on the roads around ever regularly carry more than one passenger at a time to/from a desk job (or a meal commute) that doesn't need any large hauling ever.

"Big=safe" may not be smart reason to get a big car, but it's absolutely a common ("popular") one in the US today. Just looking at how cars are advertised, there's basically two main marketing pushes "just look how safe it keeps your family" and "just look at the hobbies it could let you do that you probably won't actually do but think you will", and yes that second one is a pretty equally common reason people buy them, but both messages get about equal air time in the US and seem common in reasons people buy them.

I realize I'm very dismissive of people buying them for "hobbies/interests", but over-buying capacity based on "perceived need that doesn't actually exist" is a trap that also makes the roads less safe and should be regulated.