For all her self-consequence, Lady C. is not a stupid person I think. And as someone earlier suggested of Charlotte, Lady C. might well lack mentally-stimulating company, even if it is she herself who discourages people wanting to visit. (I had a real-world example of a woman very much like her---my mother-in-law.) A Mr. Collins or two would satisfy one of her requirements (subservience!) but not all of them. I can imagine Lady Catherine bored (as well as other things), esp. in such a "confined and unvarying society".