It's pretty clear that the launch of Modern Warfare 3 has had more negatives associated with it than positives. As poorly received as the game has been so far, Call of Duty games always sell very well. Some, clearly, more than others.
Will MW3 become 2023's best-selling game regardless? We'll have to see the overall picture towards the end of the year. One thing is, however, very clear: it has not been popular amongst Steam users.
Modern Warfare 3 launched November 10 on Steam, and elsewhere. As we tend to do, we like to look at how it has been doing on Steam (now that Call of Duty games are on Steam again). Comparing and contrasting is fun regardless, but Steam is the only major platform that reveals player data - in real-time.