The RN chose to discard the Sea Harrier in a political miscalculation. The GR9 vs Tornado debate has been done to death elsewhere; suffice to say that the decision was taken based on short-term operational requirements (vindicated only months later)
We will never know what the RN would have given up to pay for requirements and I'm not interested in getting into an RAF vs RN slanging match (steering clear of GR9 vs Tornado although interesting that Libya is seen as vindicating the decision). The RN did not "choose" to discard the Sea Harrier, rather their hand was forced (and I have to say in favour of the correct platform). The fact is (as demonstrated through history) with an airforce in charge of maritime platforms, maritime activity is seem as of secondary importance. The example of JSF is already demonstrating this with an aircraft specifically ordered based on a Maritime Strike capability being seen as something that is based ashore and happens to go to sea rather than the other way round, not to mention F35 A being discussed as an option.