The only way Unity can realistically fix it at this point is to pull a WotC and not just backtrack all these changes, but implement a legal mechanism that guarantees changes like this cannot ever be retroactively applied to past versions of the engine.
It must have felt good to say but I suspect they’d have better chance of seeing positive results if they avoided confronting the Unity team’s egos.
The only way Unity can realistically fix it at this point is to pull a WotC and not just backtrack all these changes, but implement a legal mechanism that guarantees changes like this cannot ever be retroactively applied to past versions of the engine.
I don’t think Unity will do that.