I am not sure if the second previous response was directed to me,but I'll answer <bfg>.
I DON'T know how other airlines determine who is and who is not ready for upgrade. The first 34 years of my aviation career were in a union/seniority system. I was so lucky to be able to have my first opportunity after 21 years to upgrade <bfg> and I took it and even other chance to move up with all of the Boeings. That was the right choice for me each time in restrospect.
In a non-union-non-seniority based system, someone in management and the training center makes the decision. Time and hours have some bearing, but certainly not all that goes into the decision.
Exactly what EK does is outside of my area of knowledge and responsibility. Tht is why pprune is here for those in the know to tell us.
I personally would not take a job on a "maybe" and a whim unless I had some idea of the future and had in writing what my future would entail. Time has a way of taking its toll. That's why each of us has to make our own choices and one is not necessarily good for everybody.