Americans spend a lot of time in their vehicles. Big vehicles are simply more comfortable and practical on a daily basis, at least outside of a few dense cities. If you're going to be stuck in traffic then might as well have some space to stretch out instead of being squeezed into a compact car. Safety is less of a concern for most buyers.
You can argue that this is irrational based on handling or fuel economy or whatever. But for better or worse buyers prefer size and comfort.
You can argue that this is irrational based on handling or fuel economy or whatever. But for better or worse buyers prefer size and comfort.