Sailor - you continually misunderstand the viewpoint of anyone that doesn't like Academy. It's like your mind is not open to the possibility, of lots of us, just not wanting to play it. It;s great that you love it, but there are perfectly valid reasons for others not to.
It IS an Arena Lite, there is no arguing that (watered down is much more perjorative, but could be true from a certain angle). That may be good or bad, depending on your POV, but it is very much the case. It's a subset of the rules and content, which then gives a subset of the strategy & tactics, and some of it's own.
Personally, I've never called it a rip off of MtG. What I have said, is if I want to play a quicker 2p duel game, then I'd much rather play MtG, which is quite different. Or half a dozen other CCG/LCG's to be honest.
It's the latter point that's the real killer as far as I am concerned. Academy is not a terrible game, by any stretch. It's an okay game. But I don't care whether I am playing in AW's IP or anyone elses to be honest, and if I want a game that fits that niche, there are better games, with huge pools of local players, and if I'm playing that sort of game, then I'll be picking one of those. I have better games to use my time on than play Academy, not so Arena.
Put another way - Arena is something completely unique. It's the best game that exists of that type, but in truth it has few competitors. It's my favourite game ever. Academy is a competent, but nothing special game in a field swamped by huge numbers of similar games - it's better than some, and not as good as others, but... no... therefore! there's no reason for me to ever want to play it.
As to how well Academy sells versus Arena, you will only ever get very skewed data. All Arena players will buy at least 2 copies of each Academy set, and at least 1 copy of each Arena set, whereas each Academy player will buy at least 1 copy of each Academy set. So taken on a straight unit by unit comparison, if there were equal numbers of each player, Academy would appear to sell 3x the volume of Arena!
Actually, I'm pretty sure that Arena only-players are more common than Academy-only players for the reasons above, and some number will play both. But you can't ever disentangle usage figures from sales figures. The above reason is why Academy is an easier sell commercially though (unfortunately!), which is why AW has shifted focus to it. It's also more expensive (and thus more profitable) on a per card basis.