The proliferation of dongles and adapters is evidence that not everything will make the jump to wireless. Especially since with Lightning Apple tipped their hand and revealed that their ultimate goal was to license a subset of DRM-encoded USB standards. It feels pretty obvious that Apple's movement towards wireless is mostly about killing the specter of standardized connectivity.
Look at external drives; how is wireless going to replace this anywhere? Bluetooth can't even hit SATA speeds, much less 4k streaming speeds without re-encoding and compressing the source material. You might get somewhere with WiFi Direct, but Apple doesn't support that in the first place and requires people to use their proprietary alternatives.
Seriously, I want you to sit down and ask yourself one question. If Macs went full-wireless tomorrow, do you sincerely believe that the majority of Mac owners wouldn't own new wireless dongles?
Look at external drives; how is wireless going to replace this anywhere? Bluetooth can't even hit SATA speeds, much less 4k streaming speeds without re-encoding and compressing the source material. You might get somewhere with WiFi Direct, but Apple doesn't support that in the first place and requires people to use their proprietary alternatives.
Seriously, I want you to sit down and ask yourself one question. If Macs went full-wireless tomorrow, do you sincerely believe that the majority of Mac owners wouldn't own new wireless dongles?