This is a rough calculation
The minimum sum just increased by 6% from 131k to 139k within a few years. If we assume minimum sum to increase 2 to 3% every year, we will be facing 250k minimum sum in 20 years (2032).
Let's consider an average HDB flat price now at about 500k. (I'm already underestimating, who will sell their 4 room HDB flat at 500k today?) If we assume it grows 2% a year [As it is more than capable of ], the flat price will be about 750k.
You mean an average man will need 750k + 250k = 1 million before he can take out his retirement money?
Furthermore, if you adjust this to find out his earnings in order to have 1 million CPF dollars, he must earn at least 2.7 million by his retirement age.
With roughly 30 years of working, simple math will tell us the common man must earn more than 7.5k a month in order to take out the 1st cent.