Downgrading a new Mac to OS X Tiger? I have a kinda odd question. In theory, would it be possible for a new Mac (Lets say a fancy new MBP) to downgrade from macOS High Sierra to a OS X 10.4.11 Tiger Intel build? If so, what would be the complications of doing so, and would doing so make it irreversible?
Golden Rule: No Mac can run an OS older than the OS it shipped with.

The hardware drivers do not exist, as the hardware wasn't invented at the time.

From Snow Leopard Server 10.6/Lion 10.7 you could virtualise it in Parallels etc, but nothing before that.