No! MMA gyms teach SPORT, not SELF DEFENSE! Though you can use it on the streets against inexperienced fighters, drunk and thugs, against REAL opponents, it is USELESS! This is because the sports applications have been watered down to exclude moves that might save your life one day. All the nasty moves that could cause serious damage to your opponent is left out. You also have to take into account the fact that they fight with gloves, timers, referees and doctors on call. Sports applications fall short in reality.
I would be careful commenting about things that I haven't trained. Often, your impressions as an outsider are not very accurate. Moreover, every school, and every instructor is different. I'm sure that, just as you can find MMA guys who are very sport oriented, you can also find many who are quite aware of self defense concerns who address and train for that context.
MMA is a sport, and gyms that teach MMA do generally train for sport. There are self-defense concerns that don't exist in the sport, just as there are concerns in the sport that don't factor in to self defense. But the points you draw from this strike me as mistaken and a bit naive, respectfully! I'm also a Wing Chun guy, and haven't done MMA, and so I can't argue your points from knowledgeable perspective. But I think that, if you want to argue these points yourself, you should train MMA in addition to other arts, so you know exactly what you're talking about. I think that, if you do that, you'll both improve your Wing Chun and perspective of self-defense, as well as being able to knowledgeably address concerns about where some sports training may fall short in a self defense context.
Without first hand knowledge and experience, though, it's probably not a good idea to try to argue about any aspect of this or that art