"The market defines the value, that market is made up of consumers and providers (demand/supply). It's not the one-sided bargain you make out."
In the black and white case that you make out, yes it is. If you eliminated all the people torrenting, copying DVDs and those who grey-import BDs (they still pay for it, but it's against the Studios' T&C), then you have a high-price product that not-enough people will pay full price for. How long do the Studios last then? They need mass ticket sales, otherwise the, to be frank, pap that makes up 90% of their output will make a loss.
There is even a case that, as with music, torrents INCREASE sales. Joe might not want to take his 3 little girls to the cinema, but they really want to watch Disney Princess 14. So he torrents it, they love it and he buys the DVD for their bedroom. Or they don't like it and he saves his cash.
Another case of the customer deciding (with the help of a torrent) the value of the content; less than £45 for cinema tickets, more than the £15 for a new release DVD, or no value because they don't want to see it again.