The Coca-Cola Company tried to falsify the results and failed. They then devised their own testing competition, but this time the participants knew what they were trying. This time Cola beat Pepsi.
As it turned out Pepsi was simply sweeter than Cola. And people subconsciously favor sweeter beverages. At least, in a short run.
As we know Coca-Cola has never disappeared from the market, neither have they changed the recipe. Well, they tried to but had to stick with the original one in the end.
The matter is that apart from a liking to sugar people do not buy a can of soda to make just one sip. They are going to drink the entire can. And in this case, sweetness doesn't matter that much.