It isn't just down to costs for me either. Sometimes (often, in the past) a week in Spain was cheaper then a week in Scotland or Wales, but I have yet to finish exploring the British Isles so haven't really bothered much with 'abroad'.
I am happy to visit friends in Scotland or Norfolk and base myself there for a good wonder around just because I have found something else I haven't seen yet. I get good company, good food, and places where I don't have a language or cultural aspect to cope with. I also like the comparative safety of being able to 'pop home' if I really had to.
Apparently I will be experiencing France at some point, that will be a new one for me but that wouldn't be a 'staycation'.
Thinking harder about it I think for me 'Staycation' might be the fine line difference between being based at home or based elsewhere nowadays.