The correct term for VA is Genitourinary Syndrome of Menopause (GSM). The lower urinary tract, vagina and vulva all need oestrogen. Just thought I'd throw that out there, as no-one else has mentioned the urinary aspect, which some find more troublesome than the vulval and vaginal. It is part and parcel of the same condition.
Returning to the original question of "can you get VA if you're no longer sexually active", yes of course, but those who are sexually active might notice it before the abstainers, because penetration will become painful. As to whether all menopausal women get VA, yes, most if not all do to some extent, although it's not so easy to record as some don't recognise it for what it is, or don't seek help for whatever reason, or think they have to shut up and put up.
JP x