I don’t think this is really the primary reason for this at all. There’s an element of that of course, but there’s other factors as well. This is a decent short article about it. But the tl;dr is popularity of crew cabs + a gap in recent regulations that encouraged trucks to become larger https://www.insidehook.com/article/vehicles/why-pickup-truck...
>In other words, the regulations put in place to get better mileage out of vehicles also led to an increase in truck size. “There was kind of an incentive to maybe stretch the wheelbase a couple of inches and set the tires maybe an inch [farther] apart, because you get a bigger platform and slightly smaller target,” said Edmunds. “Now, the bigger vehicle would be heavier and might use more fuel, so it’s not as easy as just doing that. But certainly there was a feeling that if they did need to make it bigger to accommodate more passengers, the fuel economy target wouldn’t be onerous. They could do it.”
That statement is not very convincing that the regulations lead to bigger trucks.
