It was obvious even in 2005 that the nature of the deal with Ryanair would drive the competition out and that's exactly what's happened. That's why Cork and Dublin will not offer a similar deal to Ryanair or any other low cost airline as they know it will simply undermine their existing business and revenue.
Also, wasn't Cork Airport offered the Ryanair deal first and they turned it down. It was then that Ryanair offered it to Shannon. Surely it should have rung alarm bells in Shannon if another airport was after saying no to the deal!