A running argument on the internet goes something like this: Is Wing Chun practical? Wing Chun is no good in a street fight. MMA fights prove Wing Chun is not practical. False.
Possibly an individual that has the incorrect mindset is no good in a street fight. The art is above average and maybe the best for street self-defense.
MMA fights do not prove that a martial art lacks a practical application for the street since streets fights are totally unlike a ring fight that has rules, time-limits, limits on legal targets and techniques. Of course, any fighting practice prepares a student in certain areas of person-to-person combat.