GP doesn't need to, as they said sommelier exams examine on blind tasting. To a level of detail far greater than I could tell you about (though that's largely training I suppose). If someone can't tell that's fine, they can buy whatever they want, but some people can.

(And I don't think many people just start buying expensive wine without ever trying cheaper, surely most start quite cheap, develop a taste for it, and work up to some subjective level of diminishing returns and not wanting to pay more.)

You can go look up what somms study for wine tasting, look at any national or international contest for blind tastings of wine/beer/coffee/spirits, or get a book on winemaking that shows how each descriptor corresponds to specific chemicals that are part of the winemaking process.

There's no need for "experimental" data on an entire field whose current foundation is the state of the art in food science and biochemistry.