It will depend upon country to country. But I think income is mostly taxed in all country dependent upon if you fall under tax laws of that country. Also which all country has zero taxation policy let us know.
Transaction fees goes to the miners who use it as an incentive to confirm your transaction. Governments do not have a viable way to apply taxation policies to every Bitcoin users due to it being pseudonymous. With that, government would be more reluctant to accept Bitcoin.