I don't think the person's size is a direct reason for the market changing to larger vehicles. Judging by the fact that the fitness clubs in my area are packed full of SUV's and trucks, yet the people inside put a high value on fitness, I don't see a correlation. It probably is closer to the size of your car and house for that matter, have been typically a measure of success in America. 50 years ago, you arrived when you had the longest Cadillac in your driveway. Small cars have always been associated with not being wealthy enough to buy something better. SUV's and trucks also have that "I am active, look at me and how active I am" look to them. This is another very popular mindset in the US. We have also entered a very odd state in which the country is all about giving the middle finger to the world and being more 'merica than in years past. This really cements buyers to buy something that is 'merican, and that is giant trucks and SUV's. Lastly, Millenials (which companies are obsessed with more than any other demographic) is growing up and moving to the suburbs and having kids. They must have room for all the kids toys, pack and plays, automatic swinging baby pods, and the rest of the crap parents feel the need to bring everywhere. They can't do that and have a car. Even my brother, who is 100% a car guy realizes that with two kids, his Fiesta has to go. The new generation car seats won't fit in the car. He can only haul one kid at a time. Back when I was a kid, my parents had an Escort and child seats were barely anything.
As you can see, there are many factors coming together at the same time which killed the car.
Gas will go up, but buyers won't drop their SUV's or trucks like they did back in the mid-2000's. The reason is that the fuel economy of large vehicles has greatly increased and now their are and will be more options for electric and hybrid SUV's and trucks. Owners won't jump into smaller cars again. Even if they wanted to, nobody is going to build cars in that segment again.