He says very little about Bitcoin, but he sees the matter from a pragmatic viewpoint: crypto currencies - that allow hiding the money from the tax man - will be stopped by the government. Government will collude with the Bitcoin foundation or just simply direct them to do it and the protocol will be modified to implement features to enable more efficiently track of the money (but even in its current form BTC is a god given gift for the tax man as by definition everything is in the blockchain and traceable.) The miners will cooperate too. In case the developers and miners don't comply - which is extremely unlikely - measures will be exposed on different levels such as ISP and OS (in the case of proprietary OS like Windows and iOs) to crack down on Bitcoin. (Of course all naive libertarian attempts like Dash and zerocash that try to implement privacy will be cracked down too).
Please note, there is no reason for government to intervene at this moment in time. Bitcoin is minuscule and insignificant terms of market capitalization and volume, used by very few users (the active 1 million users are lot less than a mediocre porn site has) so the government will step in when for some reason it will be actually popular, but at the time the government will act quickly and forcefully.