I wonder how many end users actually have a WiFi 7-capable router? It generally takes years for routers to be upgraded.
I wonder how many end users have an internet connection capable of supporting the full bandwidth offered by WiFi 7?
When it comes to networking, there are many, many factors involved, not just the edge connection. Chances are that Apple has done this research and determined that most users would not be taking advantage of the more expensive WiFi 7 capabilities, and those that need it are often plugging in a hub that has an Ethernet connection.
Not the end of the world for things like this. 99% of users likely wouldn't notice the difference. WiFi 7 is very new.