I know 3 people, personally, in their late 50's and early 60's who have no IDs. They are all white, American citizens, who were born and raised in the US, and speak fluent English. Two of the three work jobs full time. The third person is self employed.
The 2 who work at jobs are brothers. I found out that they had no IDs when they asked me for a ride to the supermarket to cash their pay checks one day. I offered to take them to their bank instead, so that they could deposit their checks, and they just gave me a blank stare, like duhhhhhh. Finally, one of them explained that they didn't have bank accounts. I was like, how can you not have at least a checking account to pay your bills? They explained to me that all of their bills: rent, utilities, etc., were paid for them by their employer. They said that they paid for everything else in cash. They explained to me that their only ID was a check cashing card from a local supermarket, where they went every week to cash their paychecks.
The other guy I know, the self-employed one, I was with him at WalMart when he tried to apply to get a cell phone from ATT or Verizon, I forget which one. The cell phone provider guy asked him for ID, and he told him he didn't have any. The guy was like, oh, ok, just give me your name and address, and he said he could run a credit check on him. My friend gave the guy the information he asked for, and we waited. Eventually the cell phone guy said something like, "Wow, this is really strange, NOTHING is coming up about you in our system. You have no history at all. I can't find anything..." My friend decided to abandon his plan to get a cell phone, because he "didn't want to get into the Man's system if he wasn't in there already..." :)
I wouldn't have believed it, either, if I hadn't actually met people, who in most ways seem normal, but have no ID. It's bizarre, but true.