I read recently a good explanation that bigger cars create an arms race. The more they are on the road, the more people decide to buy them just to not feel threatened in a smaller car ... It is a trend that started occurring in Europe also, and it is not doing any favours to emission targets.
From the article:
"The gap is closing, but the Golf finished 2021 as the best-selling new car in Europe. It was hit heavily by supply restraints, suffering a drop of 27.9% in total volume, but demand for it remains strong."
https://www.autocar.co.uk/car-news/new-cars/best-selling-cars-europe-2021