Can somebody actually shut down Bitcoin?

Bitcoin and similar tech are being used by more and more people every day. A disturbance in the force, I sense. The empire can strike back.

Now that the caps are increasing it should be somewhat valuable to speculate on how the technology can fail. In what ways, block chain technology can be attacked and can survive or fail for a while?

1. Some super power builds a quantum supercomputer and starts finding private keys of biggest cold wallets. Bitcoin value is ruined because nobody believes they are safe. People escape from block chain space fast. Shut down operation succeeds at first. But eventually ‘quantum safe’ tech is embraced. People start using a newer coin.

2. Governments in a few countries get together and shut down ISPs for a few days. Or they block international traffic. With several mining pools disconnected from each other, but still connected to exchanges and transacting bodies and real people, recording the transactions and making blocks. Reconnect the countries and the mining pools. The pool with max ‘height’ will crush other’s blocks. Complete chaos. Everybody claiming that they sent or received bitcoins during the past days. But that winner pool’s transactions are now ‘prevailing’. Bitcoin value ruined because nobody believes in it no more. Shut down operation succeeds at first. People find a way to have internet over cell phone radios. People start embracing solar / wind power to produce own energy. To be on the safe side some alt coin with a better energy efficiency is embraced.

3. Super power entity buys the core developers and stalls the coin. There will be eventually better tech from another team. People move to better tech. Shut down operation fails.

4. Super power entity grabs much of the stake if it is a PoS coin. Votes the currency and trolls it. This is the costliest option probably because entity will be staking its own investment. People move to PoW/PoS hybrid or a better tech. Shut down operation fails because it is too costly.

5. EMP weapons kill electronic devices. People go to Antarctica or deserts to buy another device. They get online and access coins. By that time price has already plummeted. Everybody installs Faraday cage in their homes.. Shut down operation ‘somewhat’ succeeds but too costly to do this for every coin.

Overall: 2nd option is probably the most cost effective. Large value holders in block chain tech, need to be prepared for everything..

What are your scenarios?