DP and I also have friends who are from Edinburgh and from other parts of Scotland, as well as from England, Ireland and elsewhere. I would have more Scottish friends here, but quite a few of them have moved to London, which they consider better for their careers than "parochial" Scotland. If my Scottish friends are outnumbered by my non-Scottish ones, that could be something to do with Scottish people not always wanting to know English people/incomers either - like what Pruni said about Oxford. It cuts both ways.
I work at home, DP cycles to work. We shop in local shops (owned by Italians and Bangladeshis) and drink in local pubs - where we're welcome, that is - oh and we did not sell up down south and trade in here, we bought here as first-time buyers. And I live in Scotland and work freelance for English companies. So I leach money out of the London-based economy and pour it all into the local Scottish economy.
Perhaps what you think us incomers "probably" do is not 100% correct because you don't know many of thm.
I thought this was interesting from RedRobin earlier:
"I'm Edinburgh born and bred and since having the DDs virtually all the new people i have met are english. i do live in a posh bit (altho not in a posh house!) and most of the other mums round here conform to what you say, ie have sold houses down south for massivo profits and have bought something fab up here. in fact i had an estate agent round here the other day who said that house prices in this area were inflated by that very fact. none of my friends could afford to live in this area now, sadly."
In other words, your mates are all local and scottish and not English, because you're not mates with those English poeple... even though they're your neighbours.