During the days when Bruce Lee was a high school student in Hong Kong, he learned how to fight in the street. Those were the days when people (sometimes even between father and son!) solved their disputes through physical fights. Nowadays the city is more civilized, so much so, if a teacher pokes his index finger a few times towards the sternum of a male student, he will get himself into trouble with the police and the court if the student complains to the authority! So, the only way to learn combat (assuming that is one's preference) is through sports-fighting in the ring (solo compliance-practice will not work). There ain't no other alternative.
Some traditional martial artists seem can't get it, and truly believe one can be trained into real fighters through martial workout and compliant-fights. That's why we have those reality-testing one-sided video on youtube where these folks being easily overpowered by ring-trained MMA fighters. Having said that I must applaud those folks who have been willing to put themselves to the tests. Otherwise a faulty belief might have serious consequence if and when these folks are being provoked by some drunks down the street.
Some tai-chi practitioners I know have a wrong belief that by training in pushing hands and some compliant-techniques, one can learn how to fight. I honestly hope that they won't get into street row with people some day, because they are my friends.
During the past few years in China, a new form of sport-ring-combat for tai-chi has been developed. Last year in Huai An (淮安), CCTV organized a full-contact tai-chi tournament. Full-contact with some limitations (like no elbow and hand strike to the head [foot strike is OK], no ground fight, no grab on gi(!) etc). Some of the fights among the contestants were quite fierce.
The interesting point on the Huai An tournament is that those qualified have to undergo a group training on tai-chi combat for 30 days, presumably the contestants have to be trained on the rules as well as on conditioning their mind and body ready for the fights, which took quite a number of rounds. The philosophy is like reality shows originated in the west whereby contestants both compete and train and learn together in the condensed period when they will be totally focused on their respective art-form for the competition: be it singing, cooking, designing, or fighting.
What is it like? Watch this video and you will be amazed. BTW, the winner of this fight eventually became the champion.