The issue with JD1/2 is that JD is a copy of Trials. XBLA really doesn't like games that are similar. So you have Trials HD, Trials Evo, and JD2 available, when arguably Trials is the gold standard.
So many games are like this. Sequels on XBLA do not do well, even if they're sequels to fantastic games (Trials Evo is about 700k units behind Trials HD, and the gap isn't closing very fast). Therefore, JD2 really isn't a great game to compare.
The better games to look at would be The Walking Dead, Bastion, or others that have released on both systems that are arguably unique. TWD is at 2.6m for XBL, and about 1.5m for iOS. Bastion is at just under 500k on XBL, and 750k on iOS (lower price point + sales). So both markets can be roughly equal if the game is good. Of course, you do have Minecraft which blows everything else out of the water.
Back from the dead, I'm afraid.
