With the likes of government , NSA ,banks etc..Could they coordinate into creating their own crypto to defeat Bitcoin?
Creating something like 'Legal Bitcoin' , invest and pump, make it succesfull? Make markets aware
Maybe even create their own cryptography where they could still be able to decypher code if they needed to?
Yes a government like the US government can create a blockchain based cryptocurrency as an official government cryptocurrency. It will be centralized and probably a closed ledger blockchain.
This differs from Bitcoin which is decentralized and an open ledger. For this reason, I dont think a government controlled cryptocurrency can kill Bitcoin or any other decentralized altcoins.
Bitcoin is independent of bank and government control so there are people that will always prefer Bitcoin over any government currency which is really one of the main reasons Bitcoin was created to begin with.