You would have to use the truck functionality quite often (at least once a week) to hit break even on the extra cost. Very few people actually need a truck this often. The monthly Home Improvement Depot + yard sales (summer months only) + etc runs just aren't as common people think it is in their minds. The best financial path is cheap car paid in cash, and then rent a truck when its actually needed for that once a month use. This avoids the daily fuel, maintenance, repair, and depreciation costs.
As for a commuter car, the cost of gas is also often over estimated due to politics. $1000 of vehicle cost reduction can buy several years worth fuel compared to the MPG gains of something more expensive.
Of course, there are other reasons to buy a vehicle. If you love trucks, then buy it because you love the truck or you love the social status, but just don't kid yourself that it is a financial decision if you don't use the truck for business at least once a week.