[watchfirst9]

Yea, I reckon from the official statistics the proportion of the labour force earning above $8k is around 25%.
Singapore's resident labour population is around 2.5 million, so we are talking about ~625k people with income above $8k. It's a lot in both absolute and percentage terms, that's why I don't understand why the letter writer is reacting like he's very surprised that there are so many people around him making that much.
The stats and what he sees on the ground tallies nicely.
As for HWZ, haha I doubt you will find a lot of the 625k people in that forum.

I not sure where you get 25% figure, because if so median wage and household should way higher.

https://blog.seedly.sg/median-income-sin...-increase/
 Data exclude full-time National Servicemen.
Data are for mid-year.
Residents refer to Singapore Citizens and Permanent Residents.
Gross monthly income from work refers to income earned from employment. For employees, it refers to the gross monthly wages or salaries before deduction of employee CPF contributions and personal income tax. It comprises basic wages, overtime pay, commissions, tips, other allowances and one-twelfth of annual bonuses. For self-employed persons, gross monthly income refers to the average monthly profits from their business, trade or profession (i.e. total receipts less business expenses incurred) before deduction of income tax.
As data are captured from a sample survey, year-on-year income changes are prone to fluctuations and should always be interpreted cautiously. Income growth studied over more extended periods (e.g. 5 or 10 years) smooths out these fluctuations and hence provides a more direct indication of income growth.

https://stats.mom.gov.sg/pages/income-su...table.aspx

Official number median wage include PRs which generally known to earn more than Sporeans 
and the wage include bonus which some get few months while others get none. 

If 25% holds water, then a company should see few workers. 
eg a company 2 manager, 2 senior engineer , 2 engineer, 2 technicians, no room for HR, admin clerk, delivery etc 
Is it common?