This is usually done because the country thinks it's beneficial for them, e.g. more tourists or easier access for people doing business. Those one-sided decisio

This is usually done because the country thinks it's beneficial for them, e.g. more tourists or easier access for people doing business. Those one-sided decisions can be ended at any time and the EU has no power to demand those nor does it. Those are not mentioned because they are not relevant to this discussion. Canada could still over visa-free access for Germans even if Canadians required visa for Canadians because they refuse to offer access for Bulgarians. It's just unlikely that it happens.