My view of Wayland here in 2021
Somewhat recently there was some Wayland related commotion in the Unix tech circles that I vaguely follow, where Wayland people were unhappy about what anti-Wayland people are doing (for example, which may have been reacting to this). Somewhat in reaction to all of this, I had a Twitter reaction:
My Wayland hot take is that I have no idea how well Wayland works in general, but I do know that for me, switching to it will be very disruptive because I'll need a new window manager and none of the Wayland ones work like my fvwm setup does. So I am and will be clinging to X.
I can't say anything about what modern Wayland is like, because I have no personal experience with Wayland. On my work laptop I use Cinnamon, which doesn't support Wayland. On my home and work desktops, I use a highly customized X environment that would not port to Wayland.
At this point Wayland has been coming for more than ten years and has nominally been definitely the future of Unix graphics for four years. But it's fully supported on all Linux graphics hardware by only two environments (GNOME and KDE, see Debian's description of the hardware requirements). Only two of the five significant Linux desktop environments support Wayland on any hardware (GNOME and KDE, with Cinnamon, XFCE, and MATE not). Canonical is only just releasing a version of Ubuntu that uses Wayland for GNOME by default (21.04), and even then it may not do this on Nvidia GPUs (cf). There are some additional Wayland 'window managers' (compositors) such as Sway, but nothing like the diversity that exists on X (although there may be good reasons for this).
Today, it's not so much that people are refusing to use Wayland, it's that a lot of people cannot. If you're not using GNOME or KDE, you're pretty much out in the cold. If you're using an Nvidia GPU, you're probably out in the cold (even if you use GNOME, your Linux probably defaults to Xorg on your hardware). If you don't use Linux, you're definitely out in the cold.
It's true that X server development has more or less stopped (eg, also), although the X server 21.1 milestone seems small right now. It's also true that the current X server works and supports a broad range of desktop environments and Unixes, and plenty of people are using those.
PS: I don't like Nvidia GPUs either and I don't use them, but a lot of Unix people have them and some of those people don't have any choice, for example on some laptops (or people who need to do GPU computation). And they work in X.
Sidebar: Some Wayland references
See the Debian wiki page on supported and unsupported desktop environments, toolkits, and so on. Debian has been using Wayland for GNOME since Debian 10, released in 2019, at least on non-Nvidia hardware. Their Wayland and Nvidia wiki pages are unclear if their GNOME defaults to Wayland even on Nvidia hardware, but I suspect not. The Arch wiki has a list of Wayland compositors, but no information on how usable they are. The Gentoo "Wayland Desktop Landscape" may be helpful, especially since it rates some of the available compositors.