Yes, however, what if governments ban it? If copamnies are forbidden to sale with Bitcoin, very few things will be able to be bought with it (only illegal). Don't you think this can drop price? You see what is going on in China already...
The fundamental value of bitcoin is that you need it to buy illegal stuff online. You can only buy drugs or weapons with bitcoin.
So as long as society outlaws stuff, and uses violence to limit people's freedom, bitcoin will be needed and have value.
Only if politicians would stop making things illegal would bitcoin lose it's fundamental value.
Ofcourse exchange rate may collapse when US makes bitcoin illegal but it will likely quickly go higher again because it's the best media campaign bitcoin can have. The Silk Road shutdown proved that already. Bitcoin collapsed for few hours and then 10 folded because silk road shutdown advertised to the world that bitcoin works.