It's a personal preference. You're right no way you'll get that back in resale. I was speaking more specifically to MartyZ with a 2014 who I assume is in his truck for a while and not going to sell it in a couple of years.
There's a lot of guys who spend way more than 4K on suspension and other upgrades that they won't get back either.
Diesel is for some not for others. I've had a diesel and they're not for me. For me initial cost, maintenance, cost of repairs and increase cost of fuel make it a no brainer to go with gas. I had a co-worker recently went from a gas 3/4 ton to a diesel. Was complaining cause his 2019 Chevy 6.0 gas only got 10 mpg the way he drives. He went to a diesel and now gets 13 mpg and he literally thinks he saving money.