But that still lets people wait until the whole season is over, watch it, then cancel. To avoid that behavior, IMO streaming will move more and more to the TV model: it's available for a limited time, maybe 1 week, maybe the last few episodes, then it's removed. If you want to watch the old stuff, pay more, either by the episode, by the season, etc. Amazon is already doing that with Fringe for example: you can watch Season 1 at no cost, but the other seasons will cost you.
Media companies are gross. It's a damn shame the media producers didn't just put all their shit on Netflix for one low price, but greed all around would have likely never let that work either.