I like the idea of "the large country house a centre of influence and patronage" and the notion that a "proper Mansion house and home [is] the theatre of his hospitality." When the text goes on to discuss that "elite families became increasingly inward-looking over the course of the eighteenth century," I wondered if it was, once again, attributable to economics.
For example, I think of Mansfield Park as being rather inward-looking (if I'm understanding the concept correctly), because Sir Thomas has other concerns on his mind (i.e., Antigua) than regularly interacting with the local community. Then I think of an opposite example, that of Donwell Abbey, which as a working concern encouraged interaction and good relations with the surrounding neighborhood. I don't know if these impressions are correct, but that was my initial thought when I read the opening of this chapter.