Depends very much on the facts on the ground. As events have shown, the writ of King’s Landing doesn’t exactly run to Dorne, let alone the Marches, especially now that Aegon’s army is on the verge of taking Storm’s End.
For example, on paper, Phillip Foote is the Lord of Nightsong, but he rather pointedly is staying in King’s Landing and hasn’t been able to lay his hands on its lands, incomes, or castle.