Thanks for the comment.
Your thoughts on the ponzi-like system of Steem is one that reflects the entirety of cryptocurrency and even fiat/stock markets themselves. The early users are the most rewarded.
I don't think there is really a right or wrong method of distribution, given each has its flaws. The problem with a fixed SP amount is that nobody would really earn anything at all considering the rewards are distributed per the dollar price. Which is why now you make more Steem per post than you would at higher prices.
It would also mean that there's still not much of an incentive to keep any of the Steem/SBD you make and increase selling pressure. Goes back to the thing I said about there being no real way of fair distribution.