The men-in-black who offer a lot of money for every coin would be effectively just backing up Bitcoin and giving huge publicity to it. I wouldn't mind that. Even if they eventually managed to get 99% of all the coins and that somehow hindered the economy, we could always start using Bitcoin with a new block chain and see how long they're going to pay us.
Governments could simply outlaw Bitcoin, as I think they have done to most other "unofficial" currencies. They wouldn't "offer" you anything but the chance to stay out of jail.