Governments exist to rule the people.  They need the money of there citizens and anyone else that does business in there country to accomplish this.  They found out they are not getting there money from these exchanges.

For example 40% of Ethereum trade happens on Korean exchanges.  That is billions of dollars a day, the taxes related to this trading is poorly regulated.  They are loosing money.  Losing money equals losing power.  What Government would allow that?

Do you actually think Bittrex and Poloniex will still be in business in a few years.  Wait till the US does their raids.  Dollars to donuts there are ongoing investigations for all major exchanges in the developed world.

Bitcoins worth is not its USD equivalent value.  Its value is estimated in the use of its technology.  Peer to peer electric cash not peer to centralized exchange.

If you want that power.  Hold your private keys. Run a full node.