It’s way, way too early to have any meaningful data on how many people have finished games they started, particularly for the group of people (which is the vast majority of normal players) who they were concerned about.
I have a total of 40 hours in. Those are pathetic numbers for a CivFanatics reader, but for a typical game buyer, you really think they’ve managed to put in 40 hours since the game was released? It’s only the hardcore who put in those kind of hours.
In those 40 hours I’ve managed to finish one game. I started a Jose Rizal game on all standard settings with Greece > Hawaii and ended up so far ahead of the AI by the Modern Age, I restarted. I played a second game with Friedrich Oblique, Rome > Spain > Prussia. I really wanted to finish a game, so I went with Tiny Map, Online Speed, Viceroy and finished a full game yesterday.
So 40 hours, 1 online-speed game finished, 2/3rds of a standard game finished. That’s with having played Civ games since Civ1 watched a huge amount of Civ7 videos ahead of time and knowing how the game works. The normies are not going to know how the game works (and the UI isn’t doing them many favors) and they sure don’t have 40 hours of game play in one week. If they’re lucky they’re somewhere in the Exploration Age in their first game. If they’re have a young kids at home or a busy job they’re probably still in the Ancient Age.