Are LTC Residents "Telling" Us that Antibody Testing is Important for Covid-19 Prioritization for Boosters?

In recent weeks, I've spoken to or read about residents of long-term care facilities being tested for Covid-19 antibodies.  Some residents, without being ill, are showing low (or even "no") levels of antibodies, despite having been fully inoculated in the spring of 2021.  This doesn't mean there was anything wrong with the original vaccinations, but it does suggest that at least for older persons, the immunity reduces over time.   As a result of these test results, the facilities are recommending that families support getting booster shots for their loved ones. That strikes me as using scientific data appropriately, to help prioritize next steps in fighting the troublesome developments with Covid-19. 

Why aren't other institutions, including universities, seeking similar information about antibodies or lack thereof?   Does it "matter" that a faculty member -- or a student -- or an administrator -- or a staff member -- was "fully vaccinated" in, for example, February 2021, if they aren't still "protected" in September 2021?  

Here's what I know so far:

• My own health insurance company requires a "doctor's order" to permit an antibody test to be covered for reimbursement.
• My local pharmacy advertised last spring that its onsite clinic would be offering antibody tests.  I learned recently, however, that it never actually set up that program.  The pharmacist I talked with didn't know why that decision was reversed.
• My regular physician said I could sign up for a booster shot approximately 9 months from my last of the two-shot original vaccination, and said that therefore I didn't need an antibody test.
• My insurance company asked whether I had a known exposure to Covid-19, implying that if the answer was yes, they would cover testing for a breakthrough-Covid infection, but not for antibody testing unless I had a doctor's order.

I realize one personal anecdote isn't evidence of much of anything.  But, is nursing home data already being generated that suggests antibody testing can supply relevant facts, perhaps facts that are "more" relevant than simply a history of immunization?