Because that is a beta build. Not the final result. Some thought it was a good idea to strip this view of all meta data. I am not one of those
I really hope that a horizontal meta data info pane is allowed in this view in the future, so we can add some data that we find really important. I do not see any reason why you should not. At the same time, you would need to choose if you really want that Big info pane to show up for every item. This could be configurable in the view options imo. For some, the big info pane really breaks the flow of theater view. This sort of things would add a whole new level to customization for theater view. Today it's quite forced unfortunately. A way to remove the forcing of big info to appear, and an alternative look of this flow view with a bit smaller covers, and more meta data would make this view complete. Now it's just for those who like bling and cover arts. I'm sure there are quite a lot of those out there, but they are not everyone...