It really pisses me off that Samsung and Moto and Apple disabled this native function. Slimport is supposed to work in new LG but it won't be out for a couple of months.I inquired about this at one point and heard nothing back. The Type C connector is capable of native HDMI output, but the hardware has to support it. I haven't heard anything about the hardware supporting it. Only thing I've seen that might come about is the OneCompute Moto Mod.
If I read correctly on the Nexus 6P, it's a USB-C plug but it's using USB2 specs. So USB2 speeds and such. USB3 should support HDMI. USB-C. Doesn't mean it will support HDMI. Has to be USB3 compliant.
It's annoying. Everyone says use Chromcast or similar device but video and sound never sync properly. People claim V20 will support wired hdmi so I have to wait and see