Seeing movies in a theatre on TV and actually owning them are three very different things. People don't all go to the cinema Because they have to see the film right away, they go because its a better experience than watching it at home. Likewise, a hardback book is a different beast to a paperback. Games however, are the same no matter how much you pay for them or when you do so.
So, if people knew for certain that the exact same product they're buying today will be reduced to a certain price at a certain date will they still buy it? Well yes actually, but not as many of them.
Obviously then the publisher has to decide if and when they will reduce their prices in order to maximise profit. I'm sure the idea you've outlined isn't new to publishers. More likely , as they employ economists more practised than you and me, they've just thought about it and rejected it







