If you let me know what city you're in I can have a look if there's any decent Wing Chun there.
Jeet Kun Do was Bruce's early vision of mma although not for ring fighting.
It has a WC base and focus also on efficiency but integrates boxing, kickboxing, Judo etc.
But this was a time when martial arts were not nearly so well known and were more secretive. Bruce learned only the first two of the three empty hand forms and the first 1/3 of the wooden dummy set and Yip Man refused to teach him any more. So he had not mastered the art when he began cross training and forming his own method.
Traditional Wing Chun is only close range so I would say not complete. But the concepts can be extended to medium range. You are right that if someone controls the range better and keeps them on the outside it makes it hard for them.
But to fight a good WC guy on the inside especially with all strikes allowed would be a nightmarish violent experience. If someone was also high level WC I wouldn't go near them even to try to take them down but rather would try to knock them out on the outside or kick and keep good range. That is their strength so why fight to it?
The debate about less rules goes back to the earliest days of the UFC.
The UFC 5 superfight was actually supposed to be between Royce and a guy called Emin Boztepe, a WC guy with a wrestling background.
I'm not a fan of Boztepe at all or his way of doing WC but the guy can fight for sure. In fact Royce and Rorion challenged him to fight in the UFC but he refused and said he would accept but only if it must be no rules at all without exception which is what NHB was advertised as. The Gracie's refused.
I include the interview here where he talks about it for historical interest.
Boztepes teacher was this guy, who was actually a catch wrestler who studied under a later student of Ip Man.
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Now, fact is in a true no rules fight against a self defense expert you would have to be on crack to accept since the possibility of getting maimed is high even in victory I don't care how many belts you have in the ring.
Now we can say that if it works it should work in combat sport without having to rely on disabling strikes which I agree which is why I would like to see wc in mma.
But I'm sensible enough to know the limits of it and that there is an unknown variable without restrictions which we can't and don't need to test.
So this is the grey area that traditional Wing Chun, Karate and some Chinese arts hover in which is why people get touchy and ease the tension by cracking jokes.
But at the same time we can all improve by embracing modern training methods and even just light sparring is a must to able to use it no matter the environment.