Especially considering the M5 iPad pro has WiFi 7.
Sounds like maybe they didn't want to try and fit their new N1 chip this go around so they could re-use some components? MacBook still has the same broadcom chip. Or for a pro differentiating feature when the M5 Pro/Max comes out later. There's a rumored MBP re-design, so I'm guessing we'll see it then along with it having the N1 for WiFi 7.
I run our office IT, and WiFi 7 is just better at managing congestion. We have a floor in a busy building and 5Ghz is chaos. 6E is fine, it's just strangely old for a company like Apple.