I agree Serenster about the invisibility of older women, been there done it, got the T shirt!
But I also think she is protected within the royal family because for some reason she gets no criticism for what she does at all. I think Andrew protects her because after all, he doesn't get the flack he deserves either. That's why Sarah stays attached to him. Charles doesn't know what to do with Andrew and by default that includes Sarah too, despite being divorced from him for decades.
Imagine meghan talking of early education of children and how important it is like Sarah just has, or crowning someone at a book signing with a plastic tiara! The internet, media and MN would explode, it's quite funny to think of actually 😂