A 5 gallon propane tank is a lot heavier than a 5 gallon gas can, and the gas can is many times made of plastic, so only a few dollars and less than a pound weight.
Many motorhomes draw their gas from the main tank - 55 to 75 gallons, so refilling is very infrequent if they are staying put for a summer - like in a National park while hosting a campsite.
Contrary to most beliefs, farmers do get home delivery of gasoline - just like a propane tank can be refilled. You can also have gas and diesel delivered to your home or home away from home. Many businesses have fueling trucks come to the construction sites to refill both gas and diesel equipment, as well as propane powered construction equipment.
When was the last time you saw a farm tractor at the local gas station? I guess it could happen, but most fuel at home, and do not pay road tax oon the fuel used in generators or off road equipment.
Fred.