GVWR definitely plays a role, working vehicles must stay cool. Hence why towing packages come with additional auxiliary coolers and bigger radiators, not just suspension. Doesn't matter if you're commuting to work by yourself, or lugging a slightly overloaded trailer with a full crew inside - total cooling capacity is key.
Simply put, many aftermarket/self-engineered electric fan setups are hard to beat a mechanical fan setup. There are great electric options out there, but you'll still need clearance to account for the extra diameter, blade pitch, speed, and an area to displace all that moving air.
You'll notice lots of factory e-fan setups are placed on single core radiators with a lot of surface area...Because they don't have the gusto to suck air through a smaller equivalent 2.5"+ thick radiator. Fan CFM ratings are often based on a static pressure with no restrictions, a hard thing to factor in when converting over. The thicker the cores, the less effective your average low-profile e-fans become.
Also not to mention, there's other engineering that coincides with all of that. Take off the plastic air dam below the front bumper on an older GM passenger car and you'll see weird cooling system behavior. They rely on that low pressure zone to assist in pulling air through the radiator at speed. If you have a fan setup that's a fraction of an inch from your accessory drive, you better believe that it's going to have a hard time working properly.
Now there's a few horsepower and a little bit of fuel economy to be had with e-fans, but everyone has to decide what's best for their application.
