Do I detect another Ryanair-bashing thread developing? What makes other airlines "legitimate", and Ryanair not so. Is a legitmate airlines one that make negligable profits, and is saddled with out dated working practises?
That said, runways cost money, and in a commercial environment that investment needs to see a return, so under these circumstances any airport operator has to weigh up the cost / benefit carefully before starting out with planning, public enquires and the like. I don't believe threats by Ryanair to pull out would make an iota of difference.