I guess living in the silicon valley you done see many old farm trucks pulling heavy all summer. I live where there are more cows than people and most of the farms use older trucks pre 1990.
Not being argumentative I have a Cummins and yes it nice to tow with the cruise a/c ice cold .
I bet you could upgrade your truck to outperform any new truck for much less than a new one
I actually live in pretty rural area where there's more deer than people. I live in the Santa Cruz Mtns, on the eastern side. There's quite a bit of farms and ranches in Morgan Hill where I live. Some folks still use old farm trucks, but the majority have newer turbo diesels.
As far as my truck, I put a LOT of money into it last year to get it driving like new. It's possible to get the 970 foot pounds of torque a new Ford puts out, but it wouldn't be nearly as reliable I don't think. That said, I have no interest in getting a new truck. If anything the new Mach 1 is calling my name.