I'm not trying to defend myself or anything since I don't even have a car, but when I did, it was always an SUV. It wasn't so much a matter of preference as necessity. I'm not exactly huge, only 6'2", but if I try to drive my wife's GTI, I'm hunched over and hitting my head on the ceiling. Only way to do it is leaning severely back with the seat reclined. Trying to be a backseat passenger in an average sedan is completely impossible. Even though it's at least possible to drive a car like that, if not comfortably, it definitely isn't safe, since visibility is shot to shit with the tiny mirrors and your head and elbows running into something every time you try to turn to cover your blind spots.
Contrast that with an SUV. No need to lean or hunch. You can see everything without trouble. You can move without trouble. It's actually possible to use the backseat.
What? I'm about the same height and drive a sedan just fine, and it's comfortable and safe. I don't know how small your wife's car is, but I've never been in one so small that I'm bumping my head in the ceiling, that would be weird.
GP is probably proportioned like Michael Phelps: short legs, long torso.
I'm of a similar height, but oppositely proportioned, and the driver's seat in most cars doesn't go back far enough that my lower thighs rest on the seat, which makes for a lot of butt discomfort on long trips.
If the seat does go back far enough for my legs to be comfortable, it's almost unavoidable that the steering wheel is uncomfortably far away, and I put the seat pretty close to bolt upright to put my shoulders closer and reduce the impression that I'm hanging on to the wheel for dear life as it's trying to pull away from me.
Bicycles are similarly problematic: I want a shorter top tube than is common for my nominal frame size, so I ride a 59cm road bike frame with a short stem and a lot of seatpost showing. You'd be more likely to find somebody with my inseam (34" [0]) on a 61cm or 63cm frame.
[0] Sorry for the mixed units. I'm giving them in the trade sizes. Road bikes are sized in metric, and pants are sized in inches, at least in the US.
Have a look at the current model Honda Accord. It's a midsize car, but the engineers have somehow managed to create an extremely roomy cabin. 6'4" people can comfortably sit in the rear seats.
The interior space of an MPV is typically bigger than an SUV.
Considering the sales numbers of MPVs, it would seem that the argument you make is not what is pushing the disproportionate commercial success of SUVs.
This problem with sedans sounds so surreal to me.
I'm 6'4" and my car is 2005 Toyota Yaris hatchback. And that cars feels comfortable without any special adjustments.
Contrast that with an SUV. No need to lean or hunch. You can see everything without trouble. You can move without trouble. It's actually possible to use the backseat.