Conclusion:
If I am wrong about these points government will come down hard on miners. They could make it illegal to mine bitcoins. Then bitcoin will lose all of its advantages compared to alternative cryptocurrencies. It will be a code like the rest of them.
I predict bitcoin to collapse in price.
EDIT: The price increasing shows bitcoin is used as a speculative vehicle. It does not demonstrate bitcoins viability as a store of value or medium of exchange.
How can you make it illegal to mine?
Governments can pass laws that make it illegal to mine bitcoins. Simple. They can raide miners houses if need be. They can threaten you with death penalities if you mine despite it being prohibited. Again its just another line of attack that is unnecessary as you already have two major lines of attack (with one already being law, ie capital gains) to make sure it wont become a major medium of exchange as I discussed in the OP.
Do you think that a government imposing the death penalty for mining will last more than 1 week ?