poloniex and bittrex are both silent for a long time 
What does it mean ? I do not understand your title and its content. Poloniex and Bittrex are old exchanges, and they went through the hype stage. Currently, other exchanges such as Binance, Okex, and Kucoin are the first choices of investors.It quite far from his question thought but yeah you are correct they have out in the market for a long time and I guess they have been outclassed by new exchanges when it comes to promotions, community activities and some other stuff that they are lacking today. They need to make any movements in order for them to catch up or else they will eventually end up losing their platform completely.