Yeah I guess it depends a lot on how many hoops your potential employer wants to jump through? I guess your sister must be an attractive hire if the school is willing to go through that process. I imagine you will see more British teachers foregoing Europe and heading to the Middle East or China if they want to teach internationally? Since the visa restrictions are the same for everyone and usually schools out there will make the process much easier. European international schools have never had to go through the visa process before and also British qualifications are no longer recognised automatically. There would be the added pain of their being 27 separate visa regimes to navigate for Europe.
The situation is developing as Covid has eschewed hiring and made schools/parents delay their hiring.
With the role I’ve just landed it was quite unusual that they basically hired me after a brief phone call. This is pretty unheard of. My only guess is that there are fewer E.U. citizens who would have in depth knowledge of the British curriculum (I’ve been hired to help a student transition from an IB school to a British curriculum one). The vast majority of my colleagues in private education are British (like 99% of them). I haven’t taught the Irish curriculum in years and would only know a handful of people teaching back there.