Actually it IS possible to change social security number, but extremely difficult and cumbersome.
I have worked with a student loan organization and one of the cases we were required to accommodate was a person changing SS number.
in fact, in conversation with a colleague who has had his tax refund fraudulently stolen for the past three years by identity thieves, he told me that that was his next step to attempt to solve the issue. I suspect it will become an increasingly likely fallout of the continued mis-use of SS numbers by private companies (who fail to protect this info)
Changing a SS is possible, but difficult and troublesome-
For example it’s my understanding that when you change your SS, your credit ratings don’t follow you. So you end up an adult (presumably) with NO credit- which is a difficult thing, given how many seemingly ordinary things require a credit check.
I’m not sure the SS-as-a-lifetime-identifier model is sustainable anymore- but I’ve no idea what could reasonably replace it…
This is what happened with me after I got married! I allowed credit checks a few times, and people often complained about the lack of information. Now that I am divorced, my credit has been destroyed! Weee!