It makes sense for the studios to want $20 - what do they get out of selling it cheaper through Apple? This isn't the music industry - movie piracy is still fairly limited (by bandwidth, resolution and time-of-release), there's no movie-Napster, and DVD sales are still strong.
If the resolution isn't complete bollocks, every iTunes Movie Store sale is a high-margin DVD coming out of their pocket.
If the resolution isn't complete bollocks, every iTunes Movie Store sale is a high-margin DVD coming out of their pocket.