For almost no individual is an 80k truck a necessity.(Businesses yes) 20k ones get the same job done. A quite small portion of the population actually needs a truck at all as evidenced by abundance of 5ft beds.For many people a truck is a necessity. And new ones are tax deductible.
Boats and planes aren't either.
If you can actually afford the 80k truck, then the 45k plane/boat is easy. All you have to do is buy a 25k or so truck and you're in the same position, but with a slightly less nice truck.
It's about priorities. If a new truck is more important than some of the best hunting on earth, that's fine. But you don't need either the truck or plane/boat. It's what you want. And what you want more, you'll put the money. Can't afford it is a reality for a lot of people, but evidenced by the amount of 80k trucks people drive, they could, if they wanted to, have the plane or boat.
I think people do this because they think it's more expensive than it is. It's not cheap by any means, but it's not unattainable for an awful lot of people, especially if they just adjust what they spend money on.