Or strong unions, one might add. But in general you are right, of course -however, public awareness is clearly what Piketty was trying to get.
I was just pointing it out because I feel that we should not let the meme that this is just in the nature of things stay unchallenged. Also, as I mentioned, I believe that it is the difference between r and productivity growth that matters, not with total growth (although Piketty does compare to total growth), when discussing inequalities.

As an aside, as Krugman mentioned today, the demographic transition, towards a drop in the working-age population, could have a strong impact on the discrepancy between r and g. So it may have been somewhat natural because we were always in growing times, and now the reverse become natural because there may be an unreversible decline in numbers.

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi