This is something which I've beleived for awhile, which is the prospect that if big governments and banks worked heavily together they'd be able to remove Bitcoin from the face of the earth. They wouldn't ban it, as that would be a tough thing to swallow for the American people as they wouldn't see a good reason to do that ( at least in my mind here) But they could just go ahead and regulate Bitcoin into oblivion, making it hard for Bitcoin businesses (buying and selling, trading, etc) to operate within their countries, or be subject to insane taxes, KYC AML and such.
Do you think Governments could kill Bitcoin?
I think a really powerful country can stop bitcoin when ever they say so. Or if multiple nations agreed to stop using it then it will be gone and extinct. Even though we say that bitcoin is forever and it cannot be stopped, A great nation that can stand up to it will be a great problem to bitcoin world.