Not true, Singapore Airlines is also well placed to use them as is any airline operating a busy route between, say, a major European capital city and New York for example. If you can operate 5 flights instead of 6 per day that leaves a slot open for something else. What the Gulf countries had were new developing airports which meant accommodating the buggers wasn't so difficult. Fitting the big bastard into Heathrow, Changi, or a host of other established and busy airports was comparatively more difficult/costly.
Biting the hand that feeds IT
