There are two distinct questions regarding Dynamic Island on the MacBook—will Apple make the notch an Island? And will Apple make the notch Dynamic? Apple could do neither, either, or both.
Regarding the Island, I don’t think the reason Apple changed the iPhone notch to a pill/island applies to the MacBook. It was basically for horizontal space limitations due to the curved corners of the iPhone display, the limited horizontal space of the iPhone display for status icons, and the “Dynamic” animations they wanted to add (this reason was suggested by another forum user and I agree). Apple had to bring the whole ensemble down away from the curved edges to make more horizontal space, but this is not needed with MacBooks.
But if they still want to make it an island, another thing is, the notch fits right within the thickness of the menu bar. The bottom edge of an island would presumably be below the current menu bar, or maybe flush with it leaving only space above, either of which would look a little weird. They could make the menu bar thicker, but that would be a waste of screen real estate. Or maybe they could shrink the island so that it fits within the current menu bar. They probably can since there’s no Face ID components to fit in there, but that would probably make for a pretty tiny Dynamic Island. I guess the island could grow vertically too when it animates to make its text more readable.
The other thing they could do is make it a pill but not an island. In other words, make the notch into a more pill shape but still attached to the top bezel.
If they do want to make it Dynamic, I’m not too sure which of these is most likely.
But regarding making it Dynamic (whether notch, island, or pill peninsula), I’m not sure it would add any value to a MacBook that the MacBook doesn’t already have or that it needs. The DI is basically trying to make the iPhone a little better at multitasking. But MacBooks are already great at multitasking. A tiny widget in the menu bar might not be compelling enough when you have bigger more functional widgets that you can place anywhere on or off screen. But then again, it might be compelling precisely because it’s a tiny widget in the menu bar—it’s a bit of constantly updating information that’s always visible (if you want it) yet doesn’t take up any desktop space. Not sure if that functionality exists currently.
But another question is, what about desktop Macs which don’t have notches? Do those not get any Dynamic treatment? Would Apple bring it across all Macs? What about iPads?
If I had to bet, I would bet the notch will remain a static notch. But I think there is a reasonable chance of some sort of dynamic implementation. Of those possible implementations, I might bet on a small island that grows both vertically and horizontally with animations, unless Face ID is added in which case I would bet it will be a rectangular notch with bubbly animations.