Hue has always been all-in on Zigbee. (incl the new 3.0 standard - https://developers.meethue.com/zigbee-3-0-support-in-hue-eco...)
Ikea has gone basically all-in on Zigbee (https://www.wired.co.uk/article/ikea-smart-home-kit-reviewed...)
Amazon is embedding it their devices (At least 4 different models include a zigbee hub: https://developer.amazon.com/en-US/docs/alexa/smarthome/zigb...)
Wifi is basically a non-starter for any real automation since it takes a boat load of power, and requires a non-local server (at least without some serious work on your part). It's a great intro spot for consumers who want to try a color changing bulb they can control with their phone, since the initial buy in cost is lower with no hub - but it's not really the same.
For z-wave on the other hand... I literally cannot find a place to buy a-19 standard socket bulbs that support it right now. Lots of "controller kits" but no bulbs.
Same for thermostats - there's like 3 z-wave thermostats on amazon right now. There are dozens of zigbee models.
Honestly - on Amazon at least, a lot of searches for "z-wave [device]" end up returning mostly zigbee results.
Ex: Go search Amazon for "Z-wave plug": Row 3 starts to return zigbee devices.
Go search again for "Zigbee plug": It's zigbee devices all the way down the page (one early result does both zigbee and z-wave, but otherwise you have scroll waaay down to see any overlap)
Basically - Having both Ikea and Amazon go in on Zigbee has radically shifted the market from where it was 3 years ago (when I would have probably agreed that z-wave was the better pick).
