The notch exists for one or two reasons depending on how you view the issue. Percentage of surface covered by screen is one of the metrics that is being used to drive the sale of new phones. So are features such as face unlock. Problem is that the level of reliablity required for high end phones, under the glass sensors aren't ready yet. At least not a price that even Apple is unwilling to charge. the notch is a comprimise, we want to have both things, even if it creates an ugly comprimise that should handle OS level info battery level, signal strength etc etc and tell app developers hands off.