Invention of the Chair, or A Hunch About Haunches

I just read a popularized account of a scientific study that claims sitting down for 5 or 6 hours a day shortens one's life expectancy more than a pack-a-day cigarette habit.  I had read a few years ago in some magazine about men's health that a lot of sitting was bad.  Interestingly, that article didn't express any concern about whether it was also bad for women.  Anyway, the idea is now backed by data.   This got me to thinking about chairs, a human invention to be sure.  Before we had chairs, we sat on haunches.  And in most cultures, not for very long at a a time.  Seems like the ability to do that for more than a few seconds requires a certain amount of physical conditioning and good balance.
So, possibly the invention of the chair was a major turning point for humanity in the direction of poorer fitness.  We all know the term 'couch potato,' but 'chair potato?' 
I then pondered other human inventions that are mostly portrayed as advances or progress: agriculture, light bulbs, fossil fuels, nuclear power, computers....  Every one of these could be examined (and perhaps should be) from the perspective of trade-offs.  When we gained from the invention of agriculture, what did we lose?  Ask the same question for each of the 'breakthroughs' on my list.
I've walked around downtown a few times these past few days and am finding the streets and most sidewalks quite icy.  There's a lot of chatter at the coffee shops and gas station/mini-marts about the risk of falling, especially for senior citizens.  As a member of that group, I usually stir up a bit of trouble by claiming to enjoy the challenge the icy conditions present.  Good practice.  Why shouldn't I have to pay attention while walking around town?  [Same question could be applied to driving.] If I  slip and fall, should I sue and expect my fellow citizens to pay for my fall?  I think not.
One impression I get from spending a lot of time watching wildlife is of the incredible levels of fitness and alertness I see.  Animals' fitness for what they do is actually very inspiring to me.  We can't live forever, but why should we sacrifice years for the sake of sitting in a chair?