Every graph I’ve ever seen of video game sales from people who distribute via Steam etc typically has an initial spike if they caught on and got featured, and then a few spikes for things like holiday sales.
Maybe the devs of the game you mentioned decided that after the initial spike had passed, and they are in a long tail period, it is cheaper to remove Denuvo.
Or they just used Denuvo to protect the game during early time when most sales happen and they removed it because they want better performance and also they want people to be able to play the game 20, 50, 100, and 1000 years from now.
I'm not sure how common that is, but I've definitely bought 2 games after the "removed DRM" event. (Basically allowing me to play on Linux in pre-steamdeck times) I'm aware that lots of people don't care.
Sure lots of people don't care, but if you save money on DRM subscription fees and see a tiny bump in sales it could be worth the tiny amount of dev time. Assuming you set it up to be easily removed ahead of time.
Maybe the devs of the game you mentioned decided that after the initial spike had passed, and they are in a long tail period, it is cheaper to remove Denuvo.
Or they just used Denuvo to protect the game during early time when most sales happen and they removed it because they want better performance and also they want people to be able to play the game 20, 50, 100, and 1000 years from now.