It's possible that there may be a role to play for passenger operations at PIK in future. Edinburgh is approaching capacity, Glasgow isnt far off too, if it can return to growth. Once they reach capacity they will stop offering cut price deals to get airlines in the door, and may even start to jack up the prices to help pay for any expansion. This will lead to an opportunity for PIK to offer cheap deals to low cost airlines like Ryanair and Wizz, possibly some of the charter operators too. flybe also hinted that they may operate a PIK-LHR flight if the 3rd runway there was approved.
Another possibility might be the island PSO flights. If Glasgow starts to reach capacity, it may be in their interest to kick out the Loganair island flights, to free up capacity for larger aircraft. These could be a perfect candidate to relocate to PIK.
There are a few possibilities, however, its a big gamble keeping things running at a loss in the hope that something turns up in future.