Taste is the second most important feature of Vodka in that it is not supposed to have one. The least important feature is whether it is made from potatoes or not. You can make vodka out of practically anything.

Isn't rubbing alcohol or hand sanitizer cheaper though?

Good vodka is just vodka that tastes less like vodka.

You can just run cheap as dirt vodka through a water filter a few times to make it basically indistinguishable from top shelf vodka.

We tested this out several times in college with blind tastings at parties.