Earlier quoted context omitted.
Deals are bilateral, but club membership isn't. You wouldn't seriously expect to be in a strong negotiating position with Amazon if you decided you wanted to leave Amazon Prime but retain some of the benefits without having to pay the membership fee, for example.
Your bad analogy is directly contradicted by Britain's past success in negotiating special conditions within the EU membership. UK's position upon entering the EEC was actually so strong that its application prompted 3 other countries to apply for membership.
UK isn't at the helm of the British Empire as well.