It's way less about device count, and more about AP density - especially in RF challenging environments.
I pretty much just deploy WiFi as a "line of sight" technology these days in a major city. Wherever you use the wifi you need to be able to visually see the AP. Run them in low power mode so they become effectively single-room access points.
Obviously for IoT 2.4ghz stuff sitting in closets or whatever it's still fine, but with 6ghz becoming standard the "AP in every room" model is becoming more and more relevant.
