Just one more point of possible failure that will end up frustrating customers. The car manufactures began using touch controls for volume, temperature, etc a few years back until, unsurprisingly, they started returning to physical buttons shortly thereafter. Software is much more prone to bugs than hardware failure. Physical buttons are best in many instances!
Do you have anything to back up your claim that physical buttons are less prone to failure than software ones? Apple engineers and managers certainly need your information as they must have somehow overlooked that fact and are blindly incorporating something that will prove to be a negative experience for their customers, resulting in fewer sales and less revenue and profits, as well higher warranty costs with even less revenue for them.