In my limited understanding there are two levels to it.

At the network level, plain Wi-Fi doesn't really cut it. To get reliable connections with lightbulbs and stuff you need a mesh network where each thing connects to nearby things and they form a network among themselves. That requires a wireless transport designed for the purpose. Zigbee is one such transport, and Thread (awful name) is a new one. Both are open standards, but the main advantage of Thread is that it doesn't need a central hub. It just needs a "border router" to talk to other networks (if things need to). Thread is based on IPv6.

At the application level, you need a protocol for controlling IoT stuff, that knows about those kinds of devices and allows an application to, for example, tell a lighbulb what colour to be. This has been done with vendor-specific protocols to date, over UDP or HTTP or whatever. Matter (also an awful name) is a new open standard for it. It can work over any IP network, including Thread ones (or WiFi or ethernet or whatever).

So between them, Matter and Thread should provide standards based connectivity and control for IoT devices, and as a key design requirement they should allow it all to work locally, i.e. without the cloud connection so many vendors have forced on people. They seem like Good Things to me.

The above is just what I've picked up and may contain inaccuracies, which I would appreciate being corrected upon.

I suspect it's a combination of NIH and the big players wanting to control the certification process and chip supply.

Z-Wave has been working perfectly fine for years. There have been protocol upgrades, new hardware, a pretty large ecosystem, etc. Zigbee apparently suffers from interop problems.

Uhh, Matter is that protocol.

Eh, matter is the xkcd#927 of "that protocol".

UDMI/DTDL/Watson/matter/ZigBee all try to do "universal device management over a single API", matter is just the latest incarnation.

Matter is already 20gb and suffering from API sprawl before it's even released. I don't think it has much of a future as "that protocol" beyond whatever corporate life support its on.

The matter and thread protocols eliminates the walled garden issues that lock you into those ecosystems, and promises greater interoperability.

It’s intended to be universal.

Matter will lock you into the ecosystem promoted by Apple and Google instead of the ecosystem promoted by the Z-Wave alliance.

Consumers want support and choice, neither of which are offered in the open ecosystem. Matter bridges the gap across all three big players.

That's a load of bullshit. With Z-Wave I have a pick of over 20-30 vendors. Z-Wave is just as open as Matter. It's just not controlled by Google and/or Apple.

You may have choice, but a vast proportion of the market aren’t even aware of it, and wouldn’t know where to buy it. They see, understand, and seek out the branding for the ecosystem that they use already.

This is unfortunate, as I like free and open as much as the next HN user, but it’s the nature of innovation and socio-technical ecosystems.