I have wondered the same thing although previous efforts - Atlantic Airways to Sumburgh 15 or so years back and Loganair to Stornoway in 2019 - didn’t see a lot of takeup. Possibly only once or twice a week at most might be worth a punt but I think only Loganair could realistically attempt it. Problem for a lot of islands is there’s only so much capacity and if people want to get there because there’s few other options there’s little incentive to add significant extra capacity. Better to funnel people onto existing flights and ferries and milk it