- Yes, plenty of people including USB-C advocates like Benson Leung really wish NVIDIA didn't drop it for the 30-series. Most new laptops have an appropriate port, however, and probably at least a quarter of new motherboards.
- A low bandwidth cable should work; if link training appropriately trains an HBR2 link then it should light up at 4k60 (or 5k60 if DSC is supported.) The more likely issue is that his original cable was one of the majority of USB-C -> DisplayPort cables that is unidirectional in the wrong direction. They only advertise USB-C -> DP, after all.
- The internal webcam and speakers are connected to the USB 2.0 bus; you can verify this in System Profiler on a Mac when connected via Thunderbolt. Whatever is going wrong with the Wacom link is not because USB 2.0 doesn't have enough bandwidth.
