As always, thank you(!) for a thoughtful response.
It's an interesting word, "entitlement." The way I look at it, I paid into Social Security all my working life so I am now "entitled" to get my SS checks. If I hadn't paid into the program, I would not be so entitled. Lately, however, the terminology has been turned on its head to mean getting something for nothing.
That said, thanks for letting me know that Lyndon Johnson's original sell of SS was that it was an individual thing. But I don't think even then that the argument would have made sense. All of us oldsters are collecting more in SS than we paid into it (which is counterbalanced by those who paid in but died or otherwise couldn't collect). An individual plan might be set up to pay you only what you individually put in.
Personally, I would be for gradually increasing the qualifying age if 1) the cap was removed, and 2) people over 50 were as hirable as people under 40.
Finally, I'm glad you emphasized my statement about immigration as a way to get more funding into the program.