It's an exaggeration. But among people who actually drink wine -- the subject of this discussion -- I suspect the overwhelming majority understand the varieties, and maybe even have a presumptive preference. People who don't drink wine aren't really pertinent.

I'm a counter-example. I drink wine. I have no idea what anything is. I've never seen Sideways, and don't know what it's about. I can tell the difference between red and white. I don't really get any of the rest of it. I still like to drink wine. Just a glass now and then. Sometimes I pick out a bottle at the store based on the look of the label.

I think it is nice to know some of the different ways to analyze reds and whites. Dry vs. sweet, tannic or not. Reds, how fruity they are and what kind of fruit (cherry, dark/stone fruit or bright and berry). Earthy/funky or smooth and light.

To me, those are things that allow you to elevate your enjoyment of tasting the wine itself. Anything beyond that (knowing region or grape by taste) is turning wine into a hobby, which is fine, but not necessary.

Naah. Maybe - maybe - people who buy wine regularly might know.

But you'll come far enough with general guidelines (older = better, except some years are very good and others... less so) to please guests. Except for the amateur vinologist, but he gets to be happy about showcasing his knowledge.