Why can't I?
It's you and I speaking. Put the general public to the side.
I don't automatically equate sales numbers with quality or the health of something, so when I say something is a sinking ship, I don't just jump to the sales numbers.
I look at it the way I look at music. The best rapper isn't the highest selling rapper.
COD as a video game has been spiraling for years. Other devs can absolutely compete, but I can make the argument that them trying to emulate COD to some degree or another is what has had them fall short each time. The competitive FPS genre, especially on consoles, feels stagnant as hell. Shoot, as I think of it now, the best FPS on consoles right now is probably Doom, but that didn't have a strong multiplayer component to it.
I'm seldom the one on this board bragging about sales metrics, frames per second, resolution, etc. (Numbers overall). Maybe you'll find a sarcastic joke here and there but I'm always on the side of the quality and experience of a game first and foremost.