On MacOS, you'll probably want to use the system settings -> network adapters (or whatever it's called) instead of the command line.
1. Make sure that the configuration on the Kindle is correct.
2. Make sure that you turned on usbnetwork on the Kindle.
3. Plug in the Kindle.
4. Make sure that you configured your computer correctly, i.e. manually assign 192.168.15.201 to the correct adapter.
All of these are required, but they're a matter of a couple of minutes on OSX. (At least, you don't have to go hunting for drivers like Windows users have to)
