It’s a very slow moving project by design for better or for worse. There also hasn’t been a ton of developer interest in the DE space in supporting it until the last few years since it would necessarily take resources away from other work, and generally X has been “good enough” until recently. I don’t have anything to back this up but I suspect that the increased accessibility of gaming on Linux as well as HRR and HDR displays entering the mainstream had a lot to do with this renewed interest.