> Isn't coordination between APs something that …

All non-consumer grade (and some consumer grade) AP systems do. Ubiquiti isn’t first, unique, or best in this category.

Re: sibling comment, and no, WiFi Alliance isn’t what resulted in this working, you have it the wrong way around.

They have a rather clean implementation of standards called RADIUS and 802.11r, if that’s what you are talking about. It’s not unique to one manufacturer, that’s the whole point of Wi-Fi Alliance standards.