This isn't streaming, its the last 50cm from your computer to your display. The 200 times more of data are already handled without a sweat by today's interfaces. Dual link DVI, from 1999, can already do more than 1080p.
DVI, HDMI and MHL all require custom hardware in the device. As the Apple engineer said, Apple are trying to avoid this.
Avoiding custom hardware in devices just seems ridiculous - to support new standards Apple are either going to have to update their chips or update their devices, and they will have to update the cables too. There's not a saving here that isn't achieved by simply using an existing standard.
Of course dual link DVI et al can do more than 1080p. They are all huge. Apple's needs to support not just today's thin devices but those for the next decade (iWatch ?).