To me, a diesel isn't really purchased for the increased gas mileage while towing... It's purchased for the power and resale value of the truck. It's a cost you will ALWAYS be able to get back out of the truck.
For example... the 7.3 powerstroke diesel in 2002 was a $6,500 option. Just for ease of argument, let's say that the mileage is 200,000 on both trucks.
A gas 2002 F250 with 200k is selling for about $4,000
A diesel 2002 F250 with 200k is selling for about $10,500
Granted, it's a hearsay analogy, but, the point is that all the "big bucks" you spend on a diesel truck, you recoup when you sell it.
For example... the 7.3 powerstroke diesel in 2002 was a $6,500 option. Just for ease of argument, let's say that the mileage is 200,000 on both trucks.
A gas 2002 F250 with 200k is selling for about $4,000
A diesel 2002 F250 with 200k is selling for about $10,500
Granted, it's a hearsay analogy, but, the point is that all the "big bucks" you spend on a diesel truck, you recoup when you sell it.