I think many people purposely do not include resale to help justify their choice. They only want to talk about recouping the upfront cost through fuel only.
The diesel engine option is one of the few engine option upgrades that actually pay for themselves and then some for most people. Other engine upgrades like going from a base 3.3L to the 5.0L in an F150 or the base 2.7L to a 6.2L in a GM will not only cost you over $2k upfront, but will also cost you more money the longer you own it due to the lower fuel economy of the upgraded engines yet no one ever seems to talk about recouping their money in those scenarios. However, any time a diesel is brought into the conversation then that is the only thing some seem to talk about.
Fact is, the diesel engine option is just like higher trim option like the High Country, Lariat, or Laramie. The $7k-11k you spent up front on these options will mostly be recouped at resale because they increase the value of the truck the same way a diesel (or any other engine upgrade option) does. At the end of 100k or 200k miles, the value of the diesel truck is not the same as the value of the base engine just like the value of a Laramie truck is not the same value as a Tradesman.