Why optical viewfinders won't disappear

I was going to title this along the lines of "Why the SLR will continue" but I think it's a bit wider than that. Also, this argument will throw up an anomaly that's worth noting.

In the digital world, it's all about battery life. And battery life is really important if you're away from electricity or needing to travel light. I regularly travel for 2-3 weeks when I might be 500 miles or more from electricity. Even when I'm not, I don't want to carry an array of batteries and chargers if I can help it.

Micro four-thirds is looking promising but has pretty limited battery life (in the order of 350 shots per charge). I regularly get 950 from my DLSRs. The difference on a long trip would be between 2-3 days per charge to 7-10 days. That's significant, the difference between a couple of batteries and a bag full.

As far as I can see, the big difference is the lower power required by an optical view-finder system. Without the screen/EVF to keep powered, the camera can use less power overall. The optical finder and separate metering systems of the SLRs are similar to the low power units of the film days.

There is that anomaly I mentioned: the Leica M9. Seems it only gets about 300 shots from a relatively high capacity battery. Erwin Puts even reckons as little as 100 using the 16 bit RAW. Can't understand why, as the DSLRs can achieve much more from essentially the same processing requirement.

It's an area that disappoints me in camera development - not enough focus on battery life. It seems as the capacities get bgger and cicuits more efficient that is ussed to pile in more features and ways to drain power. Would it be possible to create a digital camera with a stripped down processing system getting 2000 shots from a typical sized battery.