The reactions that continue in the bottle aren't necessarily fermentation. My (limited) understanding of wine-aging is that tannins will slowly fall out of solution and get denatured, making the wine have less 'bite' and be more mellow. You'll notice most aged wines have a sediment at the bottom of the bottle. There's also a bit of oxidation that occurs.I think this is the question they were getting at, if all the yeast is dead, and there is no more fermentation at all, why bother aging in the bottle??