While I agree with Skipness that PIK's future as a passenger airport is (extremely) doubtful, I'm not optimistic that the airport can make a 'small profit' on the basis of non-pax operations. The Audit Scotland report includes the statement that the business plan shows that the airport is 'not viable without Ryanair'.
Sadly I think PIK is fated to be a cash pit, with or without Ryanair (or any other realistic pax operator). Whether the Scottish taxpayers should continue to absorb PIK's losses indefinitely for wider economic reasons is a political decision. But I think we need to be realistic about the airport's financial prospects.