Poloniex will come back.
In fact, Poloniex has performed well by improving their supports, user interface, security methods, and their strategy to list new coins.
Polo isn't as big as it used to be.
Yeap, Binance is a new Poloniex in both sides.
First, they have become big, and the biggest exchange for now.
Second, they will deflate later months, or years. At that time, might be the chance for old exchanges, like Poloniex or Bittrex to come back and take over Binance.
Binance is the new poloniex. After so many KYC enforcements and locked accounts, many people left poloniex.
It is still better than nothing though.
Everthing change so fast in crypto, and investors, traders simply choose the best one for them at specific period.