Apple does it with the USB-C cable which needs to be purchased separately from the 87w power adapter for the 15" tbMBP. The cable is only USB 2, but since it's

Apple does it with the USB-C cable which needs to be purchased separately from the 87w power adapter for the 15" tbMBP. The cable is only USB 2, but since it's meant for power only, you'd probably never notice. It's quite annoying though that it's a separate accessory, and won't function as a "normal" TB3 cable or even a USB 3 cable, and likewise most normal USB-C or TB3 cables won't work with the 87w power adapter at full power delivery rates. Such a mess.