The sims outside Dabai are just to save money and time. The EK sims are so busy they can not pysically get enough time on them. Oh and yes, they are short of sim drivers also it is easier to weed out the large number who can't fly before hand.
Process change has been in the wind for some time. Will prob be used in Canada and Europe, poss even east-asia.
There will still be a selection process in DXB. You will still have to pay to get here yourself.
Dubai is very much a place you and yours should see before you come.
Keep discovering