Typical truck dealers often sell only light-duty trucks. In many ways, these types of vehicles are more similar to passenger vehicles than their heavy-duty counterparts, and many buyers use them primarily for day-to-day driving and performing light tasks.
Commercial trucks are significantly larger than light-duty trucks, and dealers who sell light trucks often have limited lot space. Commercial truck dealers often place their stores in more remote locations where land is less expensive. In addition, commercial trucks aren't regulated the same as light-duty trucks, so dealers might not have the skillset required to sell them. However, most states don't have separate licenses for commercial vehicle dealers, so a dealer who chooses to sell commercial trucks is generally allowed to do so.