Why no high end battery powered wireless speaker systems?


I would love to have a set of wireless battery powered high end speakers and subwoofers.  With so many high end powered speakers  and subwoofers around these days, it would seem to be the logical next step to make them battery powered and eliminate all the cables.  I'm a little surprised that Sonos hasn't created a wireless system yet with their Play 5 speakers -even though I don't think they have any interest in cultivating the audiophile market. What are the hurdles standing in the way of this?  Are there any in the works?   
jplunkettj
Among them, that speakers are motors, and not solid state devices. Making a smoke detector with a 5 year battery is a lot easier than making a speaker that lasts 5 hours.

Even battery powered headphone amps can barely make it to 20 hours.  Imagine how much of a battery it would take to have speakers last that long.  Then, how exactly do you recharge them? 
Here is a wonderful sounding battery based system I came across yesterday. I had no idea some AA batteries could produce such sound.
They demo several songs and it's worth the wait to hear what is capable with this kind of system.

All the best,
Nonoise
Veloce Audio makes or at least used to make an upscale "Lithio" series  rechargeable battery powered amp and preamp. They were fantastic with YG Carmels. Their price has since bombed on the used market. I would love to own them but afraid they would be boat anchors pending battery replacement availability.