So two things from the RUMOR MILL.
1) Test devices (3 XL) running Android P have gestures on by default, but it is changeable in settings.
2) Test devices (3 XL) running Android P have gestures still part of the Pixel Launcher... putting Nova launcher on the device reverts it to navigation keys.
And two things from the article that everyone reporting on it seems to have missed:
3) "While Pixel devices that are updated from Oreo will still see their three-button navigation by default with an option to switch to gestures, future Google phones (and any other manufacturer that wants it) will ship with gesture navigation turned on by default." This says, that gestures will be enabled by default. It does NOT say that there's no option to change away from gestures.
4) The editor's note, "This section has been updated to reflect that Google did not confirm that future Pixels will only have gesture navigation, simply that the default navigation system in Pie is gestures." This also says that gestures will be enabled by default. It does NOT say that there's no option to change away from gestures.
So points 3 and 4, when taken in the context of points 1 and 2 - seems to indicate that the whole internet is crying over approximately nothing.