Do you mean the future where we're streaming 4k video? If HEVC (aka H.265) lives up to its promise, 4k video will come in around a mere 50% more than 1080p does now.
Meanwhile, lossless 1080p would require 20000% more space (no I didn't add too many zeros, that's 200 times more).
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.
Apple are trying to handle all technologies without custom hardware in the device. Effectively, they have turned it into a streaming scenario. It's not as weird as you'd think -- there are USB3 video adapters that work the same way.
DVI, HDMI and MHL all require custom hardware in the device. As the Apple engineer said, Apple are trying to avoid this.
Taking 1 master protocol (DisplayPort) and converting appropriately would make a hell of a lot more sense then starting with your own proprietary format, and putting compressed video decoders in your cables.
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.
Sorry but are you talking about the right connector here ? Lightning is for the iPod, iPhone and iPad.
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 ?).
Because MHL isn't USB. It uses the same plug but runs its own HDMI hardware connection over the pins -- exactly what the Apple engineer said they were trying to avoid doing for every single hardware setup.
There's every indication that Lightning can handle much more than this but in order to get the hardware running quickly, they've reused settings that were previous used for WiFi data rates.
All we can guess is that Lightning can handle somewhere between 10Mbps (AirPlay over WiFi) and 2Gbps (native HDMI rates). We have absolutely no idea where in that range its actual capabilities lie.
I'm guessing its actual capabilities are basically just USB 2.0. Someone tore apart a Lightning-to-USB sync cable ages ago and the data pins are apparently wired straight through - so we know that Lightning can speak it natively - and given all the focus on simplicity and not doing multiplexing at the expense of more complexity in the adapter I can't see any reason why Apple would develop their own protocol.
That means that the CPU reconfigures the pins into USB2 mode, which means that Lightning can at least do 400Mbps. This is because any SoC nowadays can do low-level USB-device pinout, so it's reasonable to simply pass it through the lightning connector, unlike HDMI or DVI which require specific video encoders.
It says nothing about Lightning maximum speed. Besides, whatever maximum speed can be measured with today hw, it doesn't mean that can be pushed tomorrow with different HW in the iDevice.
Given there's nothing that can currently use more Lightning bandwidth than USB 2.0, and apparently 3rd-party manufacturers don't have access to anything except USB 2.0 and slow TTL serial, it'd be surprising if it did support anything else. Also quite expensive - Apple's hardware USB implementation is almost certainly third-party IP they've bought in and dropped into place unamended, modifying it to multiplex another protocol they don't need is a waste of money.
Besides, if we're talking about hypothetical future hardware, there's nothing to stop someone doing the same with micro-USB. (In fact, manufacturers already have in the form of MHL.)
Meanwhile, lossless 1080p would require 20000% more space (no I didn't add too many zeros, that's 200 times more).