I'd think that maybe it is because the mobile games industry is as bloated as the videogames one back in '83? Too much videogames, too expensive, and lots of crap games.
I've checked a lot of them, and I think the good ones would boil to Doom RPG and a Castlevania port. I've had no problems transferring them though, some low-level utils are capable of extracting the jars for re-installation elsewhere.
Oh, and I should mention I paid something like $3 for "Pacman", but got something called "Pecman" instead. It was a pacman "clone" with lots of bugs and very, very ugly. Sadly, the game was actually made by a software company; I wonder if Namco would mind other companies ripping off their games, but then again, it's "pecman". Ugh.