Given how many other laptop vendors do this and don't charge extra for it, I think you might be over-estimating it somewhat.

Plus Apple already does this for 20(+?) languages, some of which have difference shapes, which for a macbook means different frame milling. One more letter arrangement isn't much.

Which other manufacturers offer this? I went looking for Dell, HP, and Lenovo laptops with Dvorak and couldn't find any. Even Framework or System76 doesn't have one in offer. The separate keyboard sold by System76 doesn't offer it in Dvorak or Colemak. It's difficult to even find MX profile keycaps for any alternative layouts in my experience.

Plus we're overestimating the number of users of alternative keyboard users in the world. There's maybe a few hundred thousands of us. Compared to the millions of speakers these 20+ languages have.