Earlier quoted context omitted.
and more so, its extremely hard to track peoples blood test. Adobe Acrobat can easily change anyones name on a piece of paper with a blood test result, there wouldn't be a way to confirm this person has antibodies In Israel a high antibody blood test gives you a "vaccine passport" for 6 months. ...to get that, you sign up for the blood test using your government ID # (SSN for the US), the government gets your results…
Why is any of that easier with vaccination status than with antibody status?
For antibody status, you have to do an antibody test, which is strictly more complex/expensive than a COVID vaccine (it took 3 days when I got it done), so it's not viable at population scale.
It's similar to the reason that monoclonal antibody therapy is not a scalable treatment for COVID infection - better to minimize the chance of needing such treatment by just getting vaccinated.