It's true. If unconnected wireless earbuds existed before AirPods, I certainly never saw any.
There were many. They just weren't particularly good UX wise. Some of them were great / good / fine soundwise, but the UX typically sucked.
Most definitely they existed (even the quote admits to that), but unlike other areas, I do not see other manufacturers following Apple in either functionality or aesthetics (compare what happened with slate smartphones); and I most definitely do not even see Apple leading in any metric, specially not in 2016.