It's got absolutely nothing to do with the type of vehicle.
It's all about how much light output and the beam pattern the lamp gives. The fog lamp on the SVTF doesn't pass the light output for a fog lamp per government regulations. They honestly are only there for looks. The Mustang, Taurus, Sable and other Ford passenger vehicles are same. I did have a 00 Cougar that had projector fog lamps and they put out a lot of light.
Almost 95% of trucks I've seen have fully functional fog lamps, meaning they pump out enough light to pass the regs and don't require headlamp light to assist. Fog lamps are actually designed to be used in fog (go figure). Their beam pattern spreads light down towards the ground (more so than headlamps) and prevents glare, which is the problem with headlamps in fog.
If you've ever been in a vehicle with fully functional lamps you'd know it. They don't require a hack to get them to work, and you can tell a difference between them and a decorative lamp.
k, I'm done