Okay, you know best.
I don't really drink, however I do own a few bars and at one time owned eleven. My experience talking to bar tenders, mixologists, reps from suppliers and customers is different to yours.
I am sure that there are some people who can tell the difference between some vodkas in the same way that I am sure there are some people who can tell which variety of potatoes were used to make their French fries.
I suppose I, like many people, hold many contradictory views at the same time. For example somewhere on this thread someone said that they drink quality not quantity whilst also complaining that P&O don't sell Southern Comfort.