SUV's meanwhile are just shitty versions of vans situated on truck chassis. That's literally it. Their height makes them harder to get in and out of and to load/unload cargo from. The fact that their cargo space is finished means they're less appealing to transporting shitty garden-type stuff that a truck does easily. However they're also not arranged as well as vans for their cargo space, requiring the same aforementioned oversized wheel wells, meaning they also hold less than the vans they compete with. And, despite all of that, they also by virtue of using the same chassis, the same engine, and the same suspension components, inherit the shitty fuel economy, higher maintenance costs, rollover risk, and crash incompatibility as their truck counterparts, while offering basically none of the benefits, apart from maybe towing. As long as what you're towing didn't need to be hitched to the bed anyway.
SUV's are practical for one thing: demonstrating wealth to your neighbors, and offering you better odds in a crash with another stupid SUV. Not great odds, just better odds.
1: Note that's just the EPA's figures and doesn't account for the age of the 2004 Silverado.
Edit: This is, tangentially related, why actual tradesmen not Home Depot customers cosplaying as tradesmen, have recently begin raiding the used market for pickup trucks that are actually designed to do work, not to let grown men who live in the suburbs play an imaginary role on the Blue Collar Comedy Tour. Or just abandoning them altogether and getting a van.