AyyMD haters, I would add. For some people if their favourite brand doesn't have a certain feature then that feature is useless, until it's not because it was adopted by their favourite brand as well.Haters gonna hate.
They're bound to become more common in the 1000€+ ultra-thin segment, for instance there are already options like the Swift X that comes with an RTX 3050. The MX series might very well get replaced by low end RTX GPUs with low TDP.Gaming or "workstation"-class often do, but the lower-end laptops and the ultra-thin don't.
No matter how efficient a dGPU is, it always adds bulk, weight, cost, and power-consumption.