Geometry shaders have almost always sucked in all fairness. I'm surprised a game newer than 2015 bothered with them. It's been pretty common knowledge that geometry shaders really only work better on Intel hardware (and I'm not sure how long that lasted).

Tessellation falling short is just classic Apple, though. Shows how much they prioritize games in their decision making, despite every other year deciding they need a AAA game to showcase their hardware.

(apologies for the crude answer. I would genuinely be interested in a technical perspective defending the decision. My only conclusion is that the kind of software their customers need, like art or editing, does not need that much tessellation).