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.
What government? All the governments in the world? They could as well make it illegal to sell alcohol or cigarettes, but it doesn't stop people from investing in these branches. You are thinking too much about things you just can't predict.
Just look at technological investment opportunities of the past 20 years, if you threw money into an early Microsoft, Apple, Google, Facebook, you got a lot out of it, if you did the same with Kodak - your loss. In the recent years Nokia and Motorola lost a lot of phone market to Samsung.