You know what would end this argument? If we actually knew the sales of mana pots. Since we dont know and we never will know, we can only go by experiences in game, which will be inaccurate. I know a lot of people who buy pots from the store. Its impossible to prove because not many are willing to come out in the open and say that they do and i cant do screenshots to prove it.
The facts are that there are people who do buy pots from the store to make their game play easier. Some will burn through them and can afford the TP/$. Some stretch it out for the month. People wouldnt be buying mana pots if they thought they could beat quests/raids with just in game resources.