Well, they've changed the name from Vestibulitis (meaning inflammation of) to Vestibulodynia because the disease is more than 'just' inflammation of, and they thought the term was misleading.
It's just because you said she is being continually treated for UTI's and this is the same thing that happened to me. I was continually on antibiotics, anti-fungal medications and misdiagnosed as cystitis, thrush etc when it wasn't.
It took 2 years of them saying I had bladder infection before I finally got a correct diagnosis and that was after insisting that I be referred to a Gynaecological Dermatologist, where she finally said I had VS.
Most doctors, aside from specialists, haven't even heard of it, yet in my clinic, 20% of my dr's Gynaecological Dermatology cases were VS.
I'm joined to a support group for women with VS (there are about 200 of us in this group) and nearly all were repeatedly diagnosed with UTI's prior to being diagnosed with VS.
I'm not meaning to offend, however, and don't want to start an argument between you and BB. I just thought it may be an avenue you hadn't considered.
