The kind of message that needs to be spent about cost-cutting will not be achieved by gestures such as you suggest. If you look at the measures announced yesterday and today by the British Government, you see the scale of action that is required to even begin to convince the world that a government is serious about sorting out its fiscal problems.
You talk about saving money (amount unspecified) and then say that it should be used to purchase another CASA 235, so will that save money or cost more?
You are right that the Learjet was said to be only a short-term acquisition but at that time the Beech 200 was still in service. It has since been withdrawn and in truth the Lear is probably a better fit all round for the European flights that make up the bulk of the MATS operations.
Ireland is still not that well connected to many European destinations and successive Governments of all parties have maintained the MATS capability since the late 1970s. I can't see that changing, even if there is a change of Government in the next year or two. Given that the aircraft are already paid for, the amount to be saved is probably not enough to warrant doing away with the service. Even if this was done, you would probably see
ad hoc chartering of bizjet capacity instead to enable various ministerial and parliamentary business schedules to be met.