You're not even close....
Schooling is substantially more expensive.
High schools are about $2000 usd a month. Then sports etc are easily another $500+. Per child.
Travel - even if you go only once a year back to your home country and stay with your parents for every "holiday" that will cost you a few thousand usd a year. Which you won't have. And forget about ever going to stay in a hotel or god forbid a beach resort ever again..you simply don't have the money.
At a company like Emirates the salary is actually still a bit lower than at Cathay for similar hours flown in a month - but once taxes and bills are calculated there is NOTHING left for an FO with a kid or two at Cathay. For a captain maybe a thousand or two. And this assumes you get the hours every month. If for any reason you don't fly your full roster - like mmmm - rostering taking a flight off you or you going on leave - you lose as much as half your potential paycheck.
An FO at EK has the ability to save some money - you know for retirement and all that. At CX you have absolutely zero chance of saving a cent on FO pay. You will enter retirement with a potential 30 more years of life to finance with almost no savings. And the provident fund is at best good for about 1/3 of your retirement needs.
So the spouse has to work - but then the cost of a helper to take care of the kids while wifey works eats up half her salary if she isn't some sort of professional ..you better marry a woman/man who can earn a decent paycheck or hkg is not doable.
Housing - there is a huge difference between living in a tiny flat in hkg with your two kids and helper compared to a big (free) house in the desert...this cannot be quantified purely in dollars.
I can go on. But the que of Bright eyed applicants will probably not heed this warning so I'll stop wasting my time...