I suppose maybe it has something to do with where you live, and how you use your vehicle . Here in the Midwest we tend to drive long distances more regularly then say some people in highly populated area's back east do.
Also if you tow with your 200, 18 gal does not go very far.
When the truck is built with a 24 gal tank it would be nice to be able to us it.
As far as keeping the pump cool as with many others have stated in the past, I too call BS on that theory as to why it does this.
If the pump was to run dry sure that could be an issue, but having a full tank or 2 gallons in it I really doubt that pump is running at any sort of significant temperature difference.
Wouldn’t rather have the low fuel light come on when you had 5 gallons left and then you can figure out how far you have to drive to get gas versus come on when you have 0 to 20 miles and hope there’s a gas station within 20 miles before you run dry? As long as the lights consistent you can do the math and know that when it comes on you have about 75 miles left so I’d start looking for a gas station. More gas will definitely keep a fuel pump cooler I don’t know if it makes a significant difference in the life of the fuel pump but it’s something people might consider