Fell through has it? News to me - delayed, yes and possibly some reconsiderations given the present climate but 'fell through' ? And you should always take what The Scotsman says with a pinch of salt when it comes to PIK.
There have been a number of RAF and Loganair training flights recently as well as the Cargo 747s and 777s continuing to use the main runway so not sre where you got the news about the state of the runway.
Yes, Canadians have been using BFS on occasion (I gather due to lack of hotel accommodation at PIK) but they were in recently on 'gas an gos' so again not entirely accurate information.
There is no doubt that PIK like virtually every other airport in the UK and beyond will struggle but it is far too early to predict its demise (yet again)