poloniex of today has always reminded me of Mt Gox of 2013. they both control the majority of the market with their volume (Mt Gox 80% of bitcoin volume in 2013 and poloniex nearly the same of altcoin market today).
and with all the money that goes into poloniex it is like the Mt Gox waiting to happen and in case some day that happened it will be a very long winter... "and little children are born and live and die all in darkness while the direwolves grow gaunt and hungry"
Poloniex is far from controlling majority of the market. When was last time you looked exchange volumes?
It is only on 4th place.
https://coinmarketcap.com/exchanges/volume/24-hour/With like 7-8% of the volume.
Bithumb which is the first one is a Korean exchange with 0 fee policy and it is more like the old Chinese exchanges with huge fake volumes. it should not even be in the lists.
Bitfinex is number 2 because of bitcoin and all its volume is coming from the USD markets mostly from bitcoin.
number 3 is bittrex which has grown in volume only because poloniex started acting shady and having issues for the past months. the high volume also comes mostly from bitcoin/USDT market in addition to NEO which is not available on poloniex.
and we are on #4 poloniex. when you exclude the bitcoin markets and only see the altcoins, it is still number 1 with a huge volume and others even report fake volumes to matter in this market.