Oddly enough, that's actually backwards. Up until the 20th Century, tipping was generally rejected here in the US, largely because it was considered an old world custom. It was introduced in large part as a way to suppliment the incomes that resulted from the loss of revenues due to prohibition.
The Europeans are actually emulating the practice that was common here for the best chunk of our history.
Tipping is now an established American custom - despised by cheapskate Europeans who are excoriated on my favorite blog, Waiter Rant.