I’m a complete neophyte on US stuff - I only know what I’ve learnt here, and the following could easily be incorrect. However, the tax breaks associated with superannuation are difficult to better. You don’t pay any tax at all on your superannuation payments when you are old enough to be in retirement phase (unless you’re in a small minority), and the earnings within superannuation in this phase are also tax free. As I understand it, there is some tax associated with the accounts in the US, as they’re tax deferred.
You also get franking credits back on any dividends within superannuation that have earnt them. As I understand it, the US doesn’t have franking credits. You are also able to withdraw as much as you like from superannuation.
Before you retire, I think that the tax treatment of superannuation is also better, but I could be wrong. At a minimum, your employer must put 9.5% of your wage into superannuation, which appears to be higher than what they put in in the US. My understanding is that you actually don’t necessarily get back what you’ve put into social security if you’re a higher earner, whereas everything that’s added to superannuation automatically belongs to you immediately.
As a result of all this, superannuation probably accumulates faster than the US equivalents, and the safe withdrawal rate is probably higher. The government doesn’t want people to have superannuation left at death, so there are minimum withdrawal rates depending on your age, and these are generally higher than the 4% SWR. This can mean that as you age more of your money is outside the superannuation umbrella.
However, it doesn’t really matter if your superannuation runs out because the old age pension exists as a safety net.