I think you are very misinformed.

First off, BB banks take in more than 20 new analysts every year.

Second, I think the losers in salarysg got to stop being so myopic. Investment bankers are no where near the "cream of the crap". Most aren't even as smart as your above average computer scientist/engineer. Only in Singapore will you find this over glorification of finance and finance related jobs.

Third, there is a self selection when it comes to banking. As I have commented many times before and which this forum finds it extremely hard to grasp, there are many many capable and smart individuals who do not desire a career in finance (especially investment banking) for a broad swathe of reasons.