Good god this debate is whining even by PPRuNe's standards.
There are many, and I mean MANY (myself included) "expats" in Hong Kong who can and do survive on $45k a month quite happily (yes, with wife not working and with kid on the way). For many, that's quite a decent wage. To live in a big city ANYWHERE is expensive, Hong Kong is no different. $45k a month would be about GBP45,000 a year in the UK, or AUD/USD/CAD 67,500, but the main difference is tax. Take home pay on GBP45,000 in the UK would be about GBP30,000 if you're lucky. In HK it's the equivalent of over GBP40,000. Yes, living here is more expensive than living in a small town in the Western world, but on the whole, it's an exciting, vibrant place to live.
Also, let's not forget that the rates go up pretty quickly as an SO.
I'm ready for the flak, even to be labelled management, but seriously, let's try and have SOME kind of perspective. You will note that this is a bit of a bugbear of mine, so sorry for harping on!