It isn't quite that simple, as even in counties that "lean" one direction, there are often precincts that lean the other. Who these votes are for depends at least as much on what precincts they are from, as what counties they are from. For example, I believe many of the outstanding ballots from Maricopa are from the precinct that used the "Sharpie" (which, per the conspiracy, would be a Republican precinct) since they have to be manually tabulated.
Obviously, state officials typically know their state better -- so a governor likely knows what precincts have yet to be finished and how they lean. At the same time, the governor is trying to guess how people voted in these areas -- there is a reason we actually count the votes.