I think you have some valid points, particularly the training methodology which can make a difference between a good school and a mcdojo.
So just on the point of wing chun being tested in vale tudo. Is that guy in your photo actually claiming to be a wing chun guy? Or is he simply using techniques that are similar to wing chun techniques? It does seem a bit like if I claimed Fedor was a BJJ guy cos he uses the guard well and slaps on a good armbar.
Are there any actual wing chun stylists with a winning record in mma, rather than people who's fighting techniques are similar to wing chun?