Because they didn't. The only thing that Thread shares with Zigbee is the radio. It's a completely different standard.

Zigbee Alliance renamed themselves to the CSA. Can companies still keep making Zigbee devices after Matter? Sure, it's not impossible, but it's not really going to happen much more than somebody producing anything else obsolete.

The fact of the matter is that Zigbee isn't competing with Matter, it's being replaced with Matter. Rebranding may not be the best choice of words, but I think you're missing the point.

Confederate States of America? Ballsy move.

because they do not want you searching for protocol compatiblity, they want you to lock into a vendor

they want you to look for "Alexa" or "Google Home" or "Apple HomeKit" labels, not "Zigbee" or "thread" or "zwave"

I suspect it is desirable as one is supposed to search for the marketed products. The magic smoke that binds the device to the app or blinky lights is of little importance.

At least it wasn't Nintendo in charge of the naming, then it would be New ZigBee.

If it was MS, it would start as ZigbeeSpecial 1, followed by ZigBee 5 and be incompatible with ZigBee 3.0

edit: Just in case anyone is not following C# developments

Old: .NET 1.0 … -> .NET 4.7 -> .NET 4.8

New and not compatible: dotnetcore 1 … -> dotnetcore 3 -> .NET 5

And of course, there is their ORM which did not drop the "core" part, so for .NET 4.8 there is Entity Framework 6, the version for .NET 5 is called Entity Framework Core and reached 6 as well last year. For ASP.NET (that is, on .NET 4.8) MVC 5 is the current MVC solution, I think for ASP.NET Core (.NET 5) MVC 6 might be, but despite actually working with those technologies, I’m not sure.

ZigBii

Drop formerly MassDrop, Wise formerly TransferWise