The great Clark Terry used circular breathing routinely. Sometimes just to play long phrases, which wasn’t noticeable unless you are really paying attention; and sometimes in a very obvious way, like playing an entire chorus of 16th notes with no breath. The wonderful Jimmy Owens has also used circular breathing quite a bit, even as a young player in the early 70’s. As a teenager in the 70’s I used to practice circle breathing on a middle G for 30 minutes daily just as part of my warmup - so it’s really not something new to the trumpet….
And Kenny G’s “record” was long ago surpassed by Rahsaan Roland Kirk, who was witnessed playing for 2 hours, 21 minutes in London while circular breathing. And you can bet he was playing music, not just holding one note for an hour like Mr. G.