Definitely a tangent. But certain Lenovo X1 Carbon models have 3840x2160 displays with integrated intel graphics. (Maybe other Lenovo models too, and quite probably some from other manufacturers, I'm just not familiar with those.)

There are plenty that have 4K screens and no discrete graphics cards, the X1 Carbon from Lenovo is one, I'm pretty certain Dell, LG, etc have similar models as well.