Directors Cut

Everyone's heard of a Directors Cut, Bladerunner, Terminator 2, Aliens. Funnily enough usually films that James Cameron is the Director. They usually contain a longer cut of the film, including previously cut scenes that the studio didn't like, were under pressure to meet a desired rating or were dropped due to time constraints.
The concept is that it represents the Directors' Original vision before various parties became involved in the edit and hacked it to pieces. I get that and understand it when a directors cut is released a decade or two after the original, technology has advanced in such a way that a director is able to improve on that original concept and get closer to their first imagining. What I don't get however, is when a theatrical cut is released at the cinema, and the Directors Cut is released on DVD. There is no other excuse other than to make money, by doing that you're cheating people by changing the film and having them pay to see it on two different mediums. If the film is good enough, they'll buy it on DVD anyway. The films are made at the same time, edited together, there simply isn't enough time to edit a separate cut between the cinema and DVD release.
My case in point, Terminator: Salvation was released on two separate DVDs at the same time, the original and the Directors Cut. Avatar, is making millions at the cinema and is supposedly the best film in the world, has the most cutting edge technology, taking the movie world by storm and has been between 4 and 6 years in the making depending on the source. Then why has it already been confirmed that the Blu-Ray release will feature the Directors Cut? Is 4 years not enough to get it right James Cameron? Has the technology advanced again in 3 months? Is it outdated already? Or was all that about creating his masterpiece and a modern day spectacle all just bollocks? Well obviously, cos now he's done a better version. Unless of course he's just playing everyone for a mug and milking this cash cow for all it's worth. My prediction is shortly after the Blu-ray release, there'll then be a 3d version released, probably with an additional scene, they forgot about the previous two versions. While we are on Avatar I have to point out another thing, that Mr Cameron said it was the perfect film for a 15 year old boy and had everything they would want. Rubbish. 15 year old boys want a cross between Taken, and Emmanuelle, somebody running round killing everyone they see for revenge, pausing every 2o minutes to watch women getting undressed and taking a shower in a communal changing room, not a big blue cartoon alien version of Dances with Wolves.

Anyway, back to Directors Cuts....

Here's an idea James Cameron, GET IT RIGHT FIRST TIME!!