Like Ben said, they can't get much out there in 7.1, plus people are now doing front wides/highs that aren't specifically programmed for. We basically have 11.x or 12.x right now and nothing is utilizing it.
See, this is why we need a new way of describing the surround information. Rather than specifying content for certain channels, the information there should simply be indicating where the sound is in space. Then it's up to your system to appropriately output it based on what speakers you have and where. The current way of locking content to specific channels seems a lot more limited next to that.
