i3 will never support Wayland due to a difference between Xorg and Wayland architecture. Sway is a i3 compatible Wayland server implementation.

Long story short - Wayland is a just protocol, which must be implementend in a compositor/window manager, where Xorg is a X11 display server which can run different window managers top of it.

There is no single common Wayland server like Xorg

Motivation

X11 is being quite old and unsafe protocol, and Xorg is the implementation based on multiple extensions and hacks. Almost nobody wants to support it, and all major desktop environments are slowly switching to Wayland .