Agreed that stuff ain’t free, however some of your other concerns maybe addressed in 2024/25. Thinner OLED panels on a MacBook is claimed to reduce thickness, if a touch layer in added the thickness will remain the same plus the 1080p camera requires a minimum amount of thickness. Power consumption will be minimal and hope there is a physical switch to turn the touch screen component on/off due to accidental input. Cost increase maybe marginal at best.Cost - touch layer adds to BOM
Power consumption - layer needs power
Thickness - due to layer
Stuff ain't free.
Over the years macOS has been adopting iPadOS UX, it’s possible this will initially be a separate addition to the laptop line, a new product with a detachable screen or a merger of devices. Imagine a 13” iPad Pro in iPadOS mode when detached and when attached to the base/dock it turns to macOS while charging and the rest. Flip the display and it decodes a touch canvas while attached to the base or not. Using the base/dock allows desktop class apps. A base M# processor in the display and a base or pro/max chip in the base/dock that works together for a more powerful system and pro workflow.
The concept and idea that the late Steve Jobs and Apple through these years was that the display was not detachable from the base. I believe many windows and android tablet/laptop manufacturers have proven its possible though unpolished through they implementation.