Existing != used
It does not matter if the devs alone worked on it in isolation but at what point there was public use and how it has evolved. The earliest you could argue it was being used by user on a distro would be 2016 in fedora. Actual mainstream use in ubuntu around 2021 but optional and default literally only just this year.
We are way past the short term with Wayland!
Wayland is 17 year old.