When I worked for Loganair in the early seventies we used to fly charter and air ambulance to most of the islands and strips on the west coast. The viability of some kind of schedule for Oban was looked at a number of times but as it was a VFR only airport in those days, (possibly still is?), no service ever got off the ground as the weather factor was considered too influential. Also, it would be a very seasonal route but the operator would still be required to offer a service through the winter, likely to make a big loss!