What do you get when you plug you USB phone in your USB computer ? What about the tablet ? Why can I read files from my phone via USB but my phone can't read file from my USB HDD ?
Why is my Bluetooth headphone mono with the computer, but stereo with the phone. Why can's my NFC yubikey work with my NFC phone.
Right now, people mostly ignore it because there is generally broad support in devices provided by manageable number of generic protocols. So you mostly only have to care about the few cases when stuff don't work rather than thinking what works.
There is no reason to be overly pessimistic about USB-C, it is an incremental improvement over technologies already suffering from the same issue.