Wine is just fermented grapes. It is not magic. Expensive bottles of wine may be better on average, but largely just because they put in even more quality controls and so deliver a more consistent wine. It is not magnitudes of a difference.
People talk about wine like it is magic or high art. That there is something deeper to understand. There really isn’t.
It's not just grapes. Many wines technically aren't even vegan. Not uncommon for gelatin, egg whites, milk, or fish bladders and many other additives to be used in achieving the desired taste and color before the wine is filtered.
But grapes are not all the same: besides the taste of grapes varying depending on the soil, climate, orientation to the sun etc., there is also the judgement of when to harvest. Once in harvest season grapes can approach and then pass the desirable sugar level in a matter of days.
During the winemaking process there are many variables that cannot be codified from season to season because of variation in the grapes, such as increasing or decreasing acidity (and how), fermentation temperature, adjusting tannins, and probably more.
This is all true, but much of the variation can be controlled with modern techniques and careful monitoring. Not magic, science. Again, this has a cost, so it is not that it has no value, but it does not justify a 400% - 1000% markup.
People talk about wine like it is magic or high art. That there is something deeper to understand. There really isn’t.