think gameloft knows the answer best to your q
its not always like that at times the apps are cheaper over there, and they have price drops too
some companies compete for prices on similar games, and racing games is one of the most popular, you can expect these games (NFS/Asphalt/Real Racing) to occupy prices from 0-$1 to 6 on both stores at diff times
bit of the cost and bloat can be blamed on entire buckets of pixel densities and screen sizes to design for, think of the sheer number of unique droids in the market, to the point that entire versions of games are dedicated to the features of some droids (XHD versions of games are differently priced, you dont have diff pricing for widescreen in the app store yet, its still just for HD)
one reason for many apps to occupy the 0 price point can be that iOS does not have sub $1 pricing, something Play does have