That's not all that different than US Social Security. SS has a much lower required contribution/tax rate, but the overall scheme seems similar (lower than market returns, etc) and naming (despite SS actually being called a tax, many residents think of it as a required personal retirement savings account).

SS is different mostly in that you’re not really loaning money to the government. The money coming in today mostly goes right back out as payments.

There’s also an upper limit on SS taxable income. I forget what it is, but basically the entirety of the top quintile isn’t paying SS on their entire income. I want to say it’s like 90k, but it’s been a while since I looked.