Sales alone do not make a game a success or failure, especially when a game was selling for under half price after 2 months, success is judged by how many people actually like and still play the game which it GT Sport's case is around 15% of people who have played it.
Sales are indeed just one part of the equation and this discussion reminds me of Destiny 2 a lot. D2 came out and was met with generally positive reviews, lots of people pre-ordered it and it outsold D1 immediately. Players were expecting a bigger and better Destiny but quickly started to realize that the end-game was extremely lacking, that most of it was built around an in-game microtransaction store, that many things from D1 were missing or overly simplified and they left. Even die-hard fans, who didn't abandon the D1 ship in the most difficult moments; or the top YT content creators, who were born because of Destiny, went on streaming and making videos for other games (like Fortnite, The Division etc.), after they understood that things weren't going to get better anytime soon. I couldn't even trade my copy in because there was a ban in place (
"Sorry, we have far too many copies and nobody is buying it anymore") and now new ones are sitting on the GS shelves at 20 bucks. A triple A game that came out in September, made by Bungie, published by Activision, promoted and advertised left and right. Did It sell well? Absolutely. Was it praised by the press? Yes. Was It a success beyond sales and reviews? No. Too many steps back, not enough forward, to the point where people thought that a three years old game was the sequel to the one that just came out and not the other way around.
Anyway! I know that D2 and GTS are two wildly different games, made for completely different audiences, but the point made by Stephen remains: sales surely mean money but don't necessarily mean success in the broader sense of the word, as defined by the number of active players, their engagement and overall satisfaction with the game. No need to say that It also depends on the internal sales target, that we don't know.
Just my two cents. Sorry for the long post, hope it didn't go too off-topic with D2.
Edit: Grammar.