Silent? I don't think so. Those exchanges are old exchanges which have reputations among the other exchanges, and until now, those exchanges still active to add a new token or coins. The volume is not too small than the other exchanges, but yes, if you compare with binance, both poloniex and bittrex has a small volume. Those exchanges still survive even in the downtrend or bear market, and now, both exchanges still trying to rise again. And with binance, I am sure that those exchanges can increase the volume.