I actually don't see the government thing as an "ultimate" hurdle.

The only way to kill Bitcoin is if all governments ban Bitcoin, and I really don't see that happening.

Heck even in the U.S. things can be jumbled up.

If one state decided to adopt Bitcoin, the U.S. government wouldn't be able to prevent that state from using BTC (violation of the 10th Amendment). Sure the financial and regulatory issues would be convoluted, but from an overarching perspective the state could still allow people to transact in it, as long the state transacts with the federal government in USD.