The whole marketplace will be shaken up significantly this summer, so it's maybe not a bad idea to be looking at alternative flights.
The current transport options have been more than sufficient to meet hotel capacity in the past, but a lot of these visitors will be Europeans, perhaps spending a few days in Edinburgh/Glasgow first before heading out to the isles. This will probably not happen this summer, so instead the islands may need to look elsewhere to fill those vacancies. That may involve enticing people from elsewhere in the UK to come up to Scotland and then visit the isles using existing transport, but at the same time it may be worth looking at adding flights to Manchester or London to shorten the trip and make it more appealing.
We're living in changed times, so it might be time to think a little bit differently. What didnt work in the past may well work this year.