Why no high end battery powered wireless speaker systems?

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. 

Thanks @nonoise for the link. That is the essence of what i am looking for but in a consumer friendly package.  It would be great to eliminate all the cables and expense if possible.  @erik_squires , I was thinking along the lines of having an integrated high power rechargeable battery to power the speakers-like the 7.5 AH ones that routinely come with battery powered chain saws and leaf blowers.  I think a high efficiency speaker is only going to use around 1 watt of power most of the time and maybe 100 watts at high decibel peaks?  If those batteries will power an electric chainsaw or leaf blower for extended periods, I would think a speaker would be no problem.  

Yeah, you have much to learn, grasshopper. To get power (watts) you need amps, and (pop quiz) what else? 

SONOS makes a decent sounding battery powered (rechargeable) speaker.  While I would not use them for serious listening, they certainly sound good enough for background listening.

@millercarbon-oh wise one. If the speaker draws 100 watts, a 56volt 10ah rechargeable battery should run the speaker for: 100/56=1.786 amps per hour.   So a  10ah battery divided by 1.786= 5.59 hours of max run time. of course I could solve the problem by getting a Tesla powerwall and run the whole stereo and house with that. 

Because nobody wants one.

@ebm- ouch! You might be right.