I do agree we'll only have the Dynamic Island for 2-3 years; but this is the nature of design- you solve one problem and by solving it, introduce another problem- in this case, how to keep that area useful. Yes, it will take some adjustment, but Apple has been rather brilliant here because they made the (for now) necessary problem of the pill and dot shape cutouts arguably an asset to save screen real estate.
Yes, the DI will probably leave when the pill cutout is gone in 2-3 years or less but it will interesting to see if they keep the Face ID animations, etc., in the same place after that. It would be strange if they just put them back at the bottom of the screen where they used to be.