Bitcoin is not going to be able to bring bitcoin to it's knees unless someone who is in power in the country to be able to want this all to occur. Countries that are being led by countries that are competent and care for the survival of their own currency are going to want that to thrive.
They'll edge off any rivals in their way, and in this case, Bitcoin is going to be a rival so they're going to make sure to regulate it into oblivion to make sure it doesn't stand a chance at all.
It could bring a country on its knees If that country didn't regulate bitcoin, If they did then I don't see how this could happen as they will tax it, and make whatever rules they want and since people use exchanges and don't really care about decentralization and their privacy, this is not going to happen. In fact, It's the banking system who will bring bitcoin on Its knees If this continues.
The banking system will just be paying off the politicians in order to make this happen. Going to agree with you on the regulation though.