Effectively invisible

Penelope Lively describes the invisibility of a certain age in Spiderweb:

“A woman in late middle age is the most neutral figure of all … She poses no sexual threat nor challenge. For young men, she is of so little interest as to be effectively invisible. For women younger than herself, she is a comforting reminder that they have not themselves got that far yet, thanks be. For those around her age, she is a reassurance: we are not alone.” 

But I believe she gets the benefits wrong: 

“Accordingly all three groups are reasonably well disposed, the defences are down, an overture will be accepted with equanimity and in some quarters with enthusiasm.”