Mappers had to look listen to the description of the DM and try to draw a “good enough” map. Very easy to get things mixed up or one square off, and have to erase and redraw. “A doorway to the left” can be confusing when you’re are heading south and it on the right of your map. Or maybe the DM means the left of the map?

Bear in mind, there was often treasure hidden in secret rooms, so knowing where the unexplored space was could be pretty important.

Once in a blue moon there was a player who got a thrill from that, but most folks hated the hassle.

There was a fair deal of “rules of order” style rules in early D&D.

Ever hear of a “caller”? That was the special player in early D&D rules who got the privilege of telling the DM what the party would do. It did kind of help with big groups, actually.

Better that than being stuck as the “mapper.”