I didnt have all the documents available for my Real ID which has quite the requirements. In the limit, at least as many as any other citizenship proofing task. We can assume the greatest difficulty would be for the homeless.
It took me ~15 minutes on the social security admin website to get a card ordered to me because mine is lost somewhere in a safe. I had it sent to my house, a PO box, homeless shelter, or any other location would work too. Can be done via a library if you're homeless. Zero excuse.
It took me ~20 minutes to figure out which hospital I was born at and get a copy of my birth certificate shipped to me. See above. Likely marginally more difficult for a homeless person. Not terrible difficult though if you're not so cracked out you don't remember even the state in which you were born. Again, zero excuse.
It took me ~30 seconds to find a document to prove my current residency. Trivial for a homeless person as well. Zero excuse.
Again, in the limit, the government should provide an easier way to do this. But the pearl clutching over the difficulty is to vastly overstated.
This is simply a fantastic excuse to not require citizenship for yet another thing. Something absolutely unheard of in other western countries. I'm beginning to think all of this avoiding proof of citizenship has an ulterior motive.