You tax land, you tax imports & exports, you tax people coming & going, you tax the cars, and you tax the planes.
Governments will still be able to operate & be able to tax their slaves citizens. Cryptocurrencies may make governments a bit smaller and leaner, but they won't get rid of them.
Bitcoin will allow us a better way to send money around the world for just pennies and allow the storage of wealth in cyberspace. It will allow people an easier way to flee the worst governments.
True they can always tax the business owners then they'll pass the cost to the consumers.
No pay tax? Go to jail, that's their power. Not from the country? Prevent their goods from entering the country.
And businesses can't really hide their identity like consumers do as they have to put a public address when receiving BTC from their customers and then it is easy to track from there.