Well, if the job went unfilled then they clearly hadn't gotten
anybody who fitted, and since you won't have been the only candidates that were interviewed, and disappointing though the result may have been, it's probably not the bias you think.
There are over 400,000 English people living and working in Scotland out of a population of just over 5,000,000; that a heck of a percentage.
I know of a village in the area where you are looking to buy, where there are only three of the houses in permanent use,
every other single one is a second home. In that same area I know where the locals live in caravans all year round
Multiply that across the country and the problems are obvious. I have worked on islands where the Scots joke that if you want to hear a local accent you need to take it in with you, or listen to the stones in the graveyard.
I know of attempts to build eco villages that were totally taken over by foreigners who could afford to throw money at an 'ideal' lifestyle and not one of the local Scots ended up with any of the plots despite all their founding work on the project.
I do understand the underlying economics and I do understand the social logistics, but that you are bringing family to settle, live, and become part of the community (and as teachers you will become involved anyway) that should ease the way.
There are problems for those who do buy and then try to sell on the same kind of profit that they expect down south. It often doesn't happen, and like those who have moved to France, they find themselves stuck with either a house that will sell, but not at a price that they can afford to move 'home' from, or having to accept a greatly reduced standard of living if they do go back to England, or find themselves unable to downsize comfortably.
There is some bitterness at folks who sell up in the South, at overblown southern prices, and outprice locals just trying to find homes for their families in the area they have lived in for generations. However, nearly a fifth of our population is not Scottish by birth now, so the problem clearly doesn't deter folks.
I'm told that many English country villages have the same issues with, relatively speaking, cash rich incomers.
UK society is fluid: for some.
Best of luck finding and being happy in your new home
M