You are speaking in past tense so I will address that.
Had we gotten included in the exchanges, at the time of our snapshot anyone who had their Peerplays on any of those exchanges would have lost them. History has proven time and again that when it came to sharedrops and the like exchanges are unreliable vehicles.
Our first priority is to protecting peerplays holders, and so by offering a blockchain token on the best decentralized exchange available, it provided the best of both worlds. Despite not being at any of those exchanges, Peerplays still did very respectable volume for what little was available for trade in the market. Not only due to the very low supply, but due to most wanting to hold and not sell Peerplays.
The Peerplays blockchain launches May 30th 2017, and there is no indication that exchanges will not seek out adding Peerplays official blockchain token to their exchanges for trade.
Hope this helps clarify why the idea of having the previously traded token on other exchanges was not conducive to the security of Peerplays holders.
Also hope this further clarifies that the future is not equal to the past, and there is nothing stopping exchanges like Poloniex or Bittrex from trading Peerplays in the future.