The big three Middle East airlines have a no poaching arrangement in place so a wage cap wouldn't be too hard to agree either.
In China, a pilot can only transfer with the employers consent and with their business networks an agreement on pilot pay wouldn't be too difficult.
Cathay terms are on a down slide as well with everything from crew meals and hotels feeling the pinch. A pilots dream job in the 1980s is becoming very average for new joiners.
Singapore Airlines got rid of its expats a while back, all local terms now.
The Middle East package is nowhere near what it used to be with expenses such as rent and school fees having a shortfall, and the pay has lagged behind inflation.
It's a bit like regular buyers at a car auction agreeing not to bid against each other and deciding who gets which cars in advance.
In most cities taxi drivers are in short supply and the companies are always advertising, but this is not reflected in the pay as rates are kept low.