I wouldn't say it breaks everything. Franky it fixes / handles better issues that are common usecases today that was not the case during the time X11 was still the norm / actively maintained such as:

• Multiple monitor support with varied refresh rates
• Hybrid GPU setup (including being able to use your motherboard's hdmi socket and your dedicated gpu hdmi at the same time)
• Display scaling
• Better isolation of applications (to the deterrence of existing linux applications)

Of course granted its a new protocol, it doesn't support all the usecases that X11 was designed for due to variety or reasons (including controversial decisions)

Mind you, Wayland isn't perfect either. For example, I found out that despite Wayland having better Hybrid GPU setup support out of the box, there are applications that ended up having broken multi-gpu support (where the application in question can choose which gpu it would utilize for its processing) where it works fine X11.

With the state of the hardware we are having, it is understandable why distros have been focused on pushing Wayland as the default, although honestly, it would be wise for these distros to not completely phase out x11 because currently, Wayland isn't perfect.