Let’s cut to the chase here and flip this around. You tell people how often they need to be using the bed or towing things before you would accept their decision to buy versus rent as reasonable?
I go through periods where I tow weekly for months. Then I also have periods where I may tow nothing for 6-12 months. I rented for a bit and it was a huge pain in the ass for many reasons not to mention fairly expensive, can be so expensive to make paying the high price on a truck worth it.
If, as I suspect, you have never had the need to tow. Or do not live a lifestyle by trade/hobby that occasionally necessitates it, just say you can’t relate to the problems and inconveniences that renting poses and quit pretending nobody has thought of this before.