I was about to disagree, then I re-read the word "average." IMO, the minimum monthly benefit should be exactly at the poverty line (because anything above it is at least adequate by definition). I don't think it's necessary for the "average" benefit to hit any particular number, except that amount paid out should at least tend to remain proportional to the amount paid in.
Why? Assuming you hit the minimums for qualification(age: 62, ~25 years worth of earned income), benefits should all be the same.
Why should they all be the same? Everyone doesn't pay in the same.
Answering a question with a question? Social security is meant as a fail safe retirement mechanism. Which means it should provide everyone with the minimum retirement amount needed as long as you qualify. Paying more or less based on lifetime earning is silly, and basing it on the age you start collecting is just a way to push out needed reforms.
Now, I am asking again, why should the amount paid out be proportional to what you pay in? To screw over low income workers?
Really only because at some point, it ceased to be a way to keep widows and children from starving. At some point (I don't know when), it became an earned benefit, and it was sold that way.
"You pay in, you get back." In fact, you find this out any time you call it an entitlement. My grandparents, who had $1M net worth before my grandfather died, talked about the SS they earned, even though they really didn't need the money at that point. Same with my older retired family members.
It depends on how you sell it. Try selling it this way:
Well, when you retire at 70 (that's your only option), you will get $1000 a month (currently poverty line for a single is $12,000).
Of course, your taxes will be X% of what you earn, no matter what you earn.
vs selling it this way:
Your SS taxes will be X amount, same as everyone else's, so everyone pays the same.
In the first one, you have to sell it as - you are providing the poverty level support to people who are retired right now.
In the second one, you pretty much are selling it as "you get back what you pay in".