WHAT IS OLD WINE?

Depends on perception and taste. For some it means 10, 20 or 25 years old wine. For some 100 and over. The fact is majority of today's wines are not intended to be kept longer than couple of years. Most of them are made differently than 20-30 years ago. It greatly depends from which grapes wine is made, will it age properly and partly how it is kept. People still keep their wine and think it will improve with years. When opening the bottle they are mostly disappointed. Their wine isn't good. Honestly said, I've never had an excellent 20 years old wine. It's no problem someone is keeping it for fun and curiosity. When someone invests lots of money in worthless old wine, it can be a problem.
Something mythical about old wine persist. 100 years old bottles and older of renowned wineries reach astronomical prices. Most of them are French, sometimes Italian. I've never heard such old wine tastes excellent, or even better than much younger one. It is the journey to unknown. Like one of almost forgotten Captain Kirk and his crew.
On one hand it would be interesting to know what exactly is happening in each wine bottle and when certain wine is best to drink. Knowing it unmistakeably, the mythical, excitement and interesting in old wine would most likely evaporate to thin air.

This Barolo was still good, even after 47 years. It's colour may be brownish, but otherwise in remarkably good condition with hint of acidity, smooth, barely port taste. Ten years ago this Barolo must have been excellent.