Well, Coinbase made $1 billion in revenue in 2017. 
>>>Source : https://www.investopedia.com/news/coinbase-made-over-1b-revenue-last-year-report/
Coinbase has more brokerage accounts, over 13 million, than the trading giant Charles Schwab.
Kraken, reportedly added around 50,000 new users in a day at the end of 2017. The volume handled by these exchanges are
enormous. Now, you can see why these exchanges are adding more and more Alt coins to their service.
>>>Source : https://www.investopedia.com/news/coinbase-made-over-1b-revenue-last-year-report/
Coinbase has more brokerage accounts, over 13 million, than the trading giant Charles Schwab.
Kraken, reportedly added around 50,000 new users in a day at the end of 2017. The volume handled by these exchanges are
enormous. Now, you can see why these exchanges are adding more and more Alt coins to their service.