If they do this, it will be the nail in the coffin for me making any future Mac purchases.

That would make for a pretty terrible laptop. iPad pro with keyboard cover would be better at that point.

This is exactly what I'm expecting too. It's more practical than replacing the entire keyboard, and it would allow them to maintain their current strategy of avoiding touchscreens on the screen itself.

I’m expecting that shift to coincide with the adoption of ARM-based A-series CPUs to offset for the double energetic consumption of the screens and to provide an ”obvious to the typical consumer that doesn’t understand techy stuff” advantage from these new laptops. Late 2019 with the next iteration of macOS after Mojave seems about right, so users will be able to load iPad apps from the iTunes App Store on it from the get-go.