It’s not. It’s 100% a MacOS limitation, because you can use MST on Windows to drive multiple displays on Mac hardware, the same is likely possible with Asahi Linux if they want to support it. Apple doesn’t want to use MST because they want you to buy into their Thunderbolt displays for extra monitors, or you can just use DisplayLink if you’re desperate like me.
It’s not. It’s 100% a MacOS limitation, because you can use MST on Windows to drive multiple displays on Mac hardware, the same is likely possible with Asahi Linux if they want to support it. Apple doesn’t want to use MST because they want you to buy into their Thunderbolt displays for extra monitors, or you can just use DisplayLink if you’re desperate like me.
It is hardware limitation. Those M-series chips have just a few display controllers. Even with Thunderbolt you can’t exceed that limit.