Well, isn't that intriguing! Everything I had read--or mis-read-- indicated it was Mavericks that had stopped the UBS synching and was requiring wi-fi.
Uh-oh! Just remembered that I upgraded iTunes the other day. Yep, it's now the latest version 11.1.5 (came out in February). Let me test your statement.
I entered an event in my iPhone and one on my calendar. Just synched via USB cable. Now checking on the calendars on both.
Guess what? Even before I could finish checking and type up my reply, an alert popped up on my Mac from the event I had entered on my iPhone. When I looked at the calendars on both, they each had the other's new event.
So, you are WRONG!! The events synched both ways--via USB cable.
So, indeed, it must be Mavericks that is requiring the wi-fi synching!
Hope you can clarify...