This actually means is that these four elements are undergoing a chemical reaction every single second and this will have a significant impact on the flavour of your wine.
The water in your wine as well as these four major compounds connect, bang into each other, break and reconnect again. They do hundreds of thousands of times in the lifespan of your maturing wine. This all makes your wine richer, and provided your Bordeaux is of a sufficient quality this will improve the taste and value of your wine every single day.
As with many aspects of alchemy, this process is still not entirely understood by scientists, but what the manufacturers of great wine do know is that this process results in superb wine. The wine ageing process is one that has been perfected over the centuries through trial and error, which is why we are today left with the sumptuous wine we pay so much for as investors and collectors.