Multiple vehicle insurance issues.?

I’m trying to figure out something that doesn’t make sence about insuring multiple vehicles.

So I already own a car, and two motorcycles, plus I have my GF’s car on my policy for the multi car discount. I’ve shopped around LOTS, and have found the cheapest insurance I can find.

Heres the thing, I want to also buy a truck. Now I’ve called all around for quotes, but they all say the same thing. Basically my truck will cost just as much to insure as my car. Including paying full liability insurance on both vehicles.

This doesn’t make sence to me. Why do I need to pay full price for liability coverage for both of them, when obviously I can only drive one at a time? What if I were to have 4 cars? I’d have to pay full price for all of them even though I’d only be driving one at a time?

The way I see it, it shouldn’t cost any more for liability on a second or third vehicle. A little for comprehensive maybe in case one was broken into or something, but why should I pay full price for multiple vehicles I can’t possibly even use all at once.

Is there any sort of insurance company out there that does things differently? Any way I can basically just pay one reasonable price that covers whatever vehicle I decide to drive?