I said "start off with very low salary". When I said 3k p/m, I'm referring to the starting salary.
If you know the private banking industry well enough, you know you don't start off as private banker. Private bankers dont' typically have many front office undergraduate positions. (those I know joined via some sort of management trainee program) If you start out in private banking without a portfolio, without prior experience in wealth management (e.g. via consumer banking), you will probably be doing adminstrative/support work as an assistant. The time it takes for you to become a private banker (defined as point person, in-charge of a network of HNW client. i.e the face of the bank) is varied and depends on many factors.

Those initial 1-5 years, up till the point you become senior enough to be incharge of a set of P&L, you typically don't earn much. You become decently paid only when you start handling your own portfolio. Typically by then your rank is VP and above. You would probably be leading a team of support bankers. "Decently paid" = I imply around S$15-20k (base p/m). Which if you are working in the banking industry, this shouldn't be a surprise to you.

And if you are in the banking industry, you will also know that it is not the base pay but the variable component that makes the real difference in total compensation. What is the typical "bonus" a VP in private banking get? This is a debate in within itself. From my experience, and from the payrolls that I've come accross, there are not many above 100k per year. As with most sales type profession (you know private bankers are ultimately judged by revenues right?) (e.g property/insurance agent) there are outliers that earn 6-7 digits in bonuses.