I'm close with you on this. I have believed for a while now that the American Dream is revenge. We love revenge as a society.
Maybe humans love revenge as a species. I don't know, I'm not travelled enough to really speak about other cultures.
But from winning the lotto and quitting your job with a big "fuck you guys" to postal workers going postal, to columbine, to "nuke the entire middle east" and how we treat criminals (we want punishment a lot more than we seem to want rehabilitation), we have a guttural response to everything. We have been hurt, and thus we will seek to hurt. Perhaps we aren't strong enough (money, influence, physical strength, etc) to take our revenge, but some day... some day we'll be the badass who will lay the smack-down.
I'm going to go back to lurking for another year or so now.
My point is that you don't get free energy... you could eliminate those extra batteries, but to get the same life, you'd need to replace them with a single larger battery. That single larger battery probably wouldn't fit in the cover as well as the lots of little ones.
An example: The CR2016 batteries used are 90mAH, 1.6 mm thick, and 20 mm diameter. Replacing this with a DC/DC converter (at a very generous 80% efficiency - at currents this low, the power taken by the generator is significant - the real efficiency would probably be in the 40-50% range) would be a single 675 mAH battery. That's a CR2450 battery -- 5 mm thick (3x thicker) and 24mm in diameter.
Pricewise, CR2016's are $0.18 each, qty 5000 (Esquire ordered 1.4 million batteries). I didn't find bulk 2450's, so I compared the same manufacturer from the same vendor - the price was 2.66x the cost of the 2016 -- so, I'd guess $0.48. The savings is 6*0.18 - 0.48 = $0.60. At 40% efficiency (two 2450's), the savings is $0.12 -- minus, of course, the cost of the converter, which is non-trivial. You need the driver chip (usually not cheap) and a pair of capacitors (high quality, or else you'll get EMI).
The one day you'd sell your soul for something, souls are a glut.