Few Guaranteed Returners......
About the time EK and the other sandpit airlines start to rehire, it is likely that other airlines around the globe will be doing the same. Given the possible pent-up demand, not many experienced pilots will wish to jump through all the hoops to reinstate themselves at companies which have treated them so shabbily. Selling-up, moving, immigration, house-hunting is all a stress, on top of simulator and line-training. Most non-locals will look to stay in their countries, if at all possible. Non-union employment protection will be a further serious consideration.
And the new T & C's are unlikely to be good anywhere, which removes the prime motivation for living and working in the desert cities.
Nevertheless a few optimists will rush back, eager to rejoin. They will be sorely disappointed, I feel, but there are some who do love the "lifestyle" out there.
With no particular axe to grind, and having had the experience of living and working out there, I foresee a major recruitment and training issue facing the ME carriers, in 2021 and beyond. The major competing carriers worldwide will not permit these airlines to gain competitive advantage so easily again.
And of course, I could be completely wrong. Time will tell.