Reason #2. They're starting to feel like a cheap way to generate publicity.
Want to get people interested in your show? Hire someone to make a hologram! That seems to be the general philosophy right now. It's not that the world needs holograms or that they add a lot to a show. It's just that if you have one included in your show, people will care about it, regardless of how the rest of the show looks. The hologram has essentially been reduced to a publicity stunt.
Photo Credit: Boston Herald