I only know central Florida, once you are finished ordering like coffee or desserts. They want you gone, that table is just dead everything to the business. It is not selling food nor paying more tips and is probably even an insurance risk with idle people just sitting around and not getting out of the establishment ! ! !
My server wants us gone so they can seat another tipper : ) The times when we have hung around you can sometimes get a vibe from the staff that it really is time you vacated the premises . . .
As I said that is just my tiny piece of a very very big country ; )
I've worked in FL myself, and yes that's definitely true of the vibe - not only there but almost all big city style places, or anyplace that's pretty busy in general. We use the word "campers" in a negative sense when people hang around - negative because we want new people at the table to start the money cycle over again. "Turn and burn" is how it's said, in our lingo. The server's assigned section only has so much "real estate" vs the hours of operation (or of "the rush") so he/she/I has a real sense that a table "camping" is quite literally costing them income the longer they sit.
Lower volume places it won't be such a big deal, because there's no one to replace you with waiting, and you might feel more casual, like it's not frowned upon to linger. But extremely high volume places you might be strictly informed at the beginning (or when your reservation is made) that you have a 2-hour maximum. Or perhaps the manager will finally come and tell you that they need the table and you have to go - ieven if they just move you to the lounge.
It is kool that you are outlining these issues, and your book sounds like an essential read. A nice helpful advice book : )