The Emin Boztepe vs William Cheung video is more of a "Gracie in Action" type of video,
if it makes a point, it is that most 1 to 1 street fights ends up in the ground (Bjj theory).
Therefore, it showcases Ermin' ground game and not his wing chung game.
Bruce would probably have faced a similar fate if he had met the gracies in the 60's or 70s.
and he would have grown a lot from it, modern mma would then have been born at that time...