Ondolindë
Emperor
Tall is basically a few cities (3-4 cities for example) but a few powerful governors while playing Wide is you are spread out with lots of cities but need lots of governors to keep all cities under control.
Not necessarily.
What tall and wide mean is just different focuses. A tall play would focus on developing most if not each city but don't mean having few cities. Wide mean there is a priority on acquiring new cities instead of developing cities.
I think one of the reasons Tall is still seen as 3 or 4 cities is due to luxury resources being limited to only 4 cities in Civ VI. This, along with 4 cities historically being the usual sweet spot in Civ V, tends to make people still feel that same number applies to "Tall" in Civ 6 as well. Once you go past that you are starting to get into a hybrid kind of scenario.
That is exactly what I meant by "these days". I figure we all have a notion of what it means in numbers to us by previous Civ games, Civ V for example, but I think Civ VI has changed that for me because I agree that it also means more digging deep into developing your cities to the max possible (and Civ VI gives you more mechanics to do so) which having fewer cities can certainly allow you to d0; you are not going crazy and through the motions at times with too many cities. As numbers go, I would probably think that for me it is shifting up one city, meaning 4-5 cities now.