As a sound designer, I feel that I have an obligation to inform you all about some of the many layers of problems here.
1. Contrary to what you may think, this is not a Broadway centric issue, the FCC didn't decide they all hate broadway all of a sudden, but anything with a wireless mic, rock and roll, sporting events, etc. This is just a result of a confluence of factors. A: The shift to Digital TV (see point 2), B: Powerful cell phone lobbies (how else do you think Verizon V-cast works?), and C: The inevitable shift in FCC commissioners which will come with a new President.
2. Wireless microphones use the same radio spectrum as Television. As all TV is shifting to digital transmission, this is already going to cause a considerable drop in available frequencies. Since an analog station will have only three or four spikes within a channel spectrum, but a digital channel will kill the entire bandwidth of a channel. They also want all channels below a certain frequency (Somewhere in the 700 MHz range), so no matter what, many wireless channels already purchased are already illegal.
note to temms, the reason that a Wi-Fi system won't work is latency, aka delay. It would seem that the internet and a wi-fi network is instantaneous, but it's not, a difference in 25-30 milliseconds could be perceived by anyone, and is frankly bad.
3. Another point to consider. Consumer sound systems today are vastly superior to professional sound systems of the 1980's, let alone the 1950's, your average broadway patron probably has a 5:1 home theater system in their living room, and as consumers, they expect the system in a theater to sound crystal clear and better (read as louder) than their living room. My biggest complaint in this category is it makes the sound scape very planar, as in coming from a single plane, i just think that if a set is in 3 dimensions, the sound should be as well.
4. I find it interesting that you all focus upon the upper end of the dynamic range, of course Paolo Szot could fill the Beaumont with no effort, but I feel that microphones are more important for the quiet end of the spectrum, allowing for greater intimacy within a piece. Take for example Paolo in This Nearly Was Mine, thanks to the amplification, he can make the start of the song that more quiet and subtle so that when the build kicks in towards the end the dynamic range is set up so he doesn't have to crank it to eleven.
The one show everyone on Broadway is waiting to see: Twyla Tharp presents: Big Bottom - The Spinal Tap Jukebox musical!