At this point, MMA is the best we have and other systems should either prove that they are still competitive or stop pretending to be able to fight more effectively.
In China, lei fights occured for hundreds of years. A martial artist would set up a platform and ask people to fight him under a ruleset he created (his platform his rules). Challenge matches were common, often with agreed upon rules. These one-on-one prearranged fights were considered as the top indicator of fighting prowess and when a fighter was victorious over a rival, the loser's students would often go over to the winner or at very least leave him.
Today, virtually every time an MMA fighter faces a TMA fighter, he wins. This has given us spectacles such as MMA fighters with six months on part time training destroying lifelong traditional fights who operate their schools full time. Virtually every TMA man who has tried has failed - the Gracies, who are today far from the top of the MMA world have racked up literally thousands of victories under no or very few rules. Truly talented TMA fighters like Keith Hackney and Ron Van Clief have admitted the superiority of the new fighting style.
In the earlier days of mixed martial arts, fights in the hotels and bars surrounding the venues were fairly common. Though today this has largely passed, at one point virtually every UFC was followed by someone being jumped in the lobby. Some of these turned into mass brawls while others were one-on-one. One was fought 3 against 2 in an elevator. Several UFC competitors were attacked by street thugs in or around their hotels in an attempt to prove their toughness. The sheer fact that these people didn't say "hey, our tounament fighting is totally useless 'on the street'" should say something.
Even more relavent is the fact that many earlier UFC fighters were at one point streetfighters. Others were highly trained and very experianced TMAists. Yet, they gave up their old training for MMA preparation. If these things worked better, they wouldn't have changed. While many champions of the TMA's sport world, and several of its higher level non-competitive fighters have switched to MMA, no major MMA fighter has ever quit to study TMA.
In their day, the creators of many TMA systems were similar to todays MMA fighters. Unlike today's TMAists, they took their strength seriously. Many lifted river rocks regularly (a rather primative, though effective form of powerlifting). Others ran considerable distances building aerobic fitness. Several CMA forms are intended as isometric exercises. Often, they relished the idea of competition and actively sought out other martial artists to challenge. They then modified their styles to be more effective.
Bruce Lee pointed out that the personal insights of an effective fighter were often turned into static imitation by the kool aid drinkers of the world who refused to acknowledge that the originators were effective competitive fighters who won matches and trained for strength and speed.
Just as Royce Gracie was a dominent force in his origional UFC fights against all comers but now is little match even for a man he normally outweighs by 15 lbs., Yang LuChan and his like were truly phenomenal match fighers in their own day whose styles are today practiced in an ineffective manner and whose practitioners can no longer effectively face off against modern fighters.
Many TMA practitioners have fallen back on a weak and tired appeal to authority in the form of saying that their style's origionator was more street tested than modern MMA fighters. Perhaps true, but if his martial arts descendants can't fight, it doesn't matter whan his capabilities were - it is YOU who will fight, not him. The idea that combative knowledge is static is also rather absurd.
Today, we believe in things like blood circulation, even though the Roman surgeon Galen, who performed more operations than all but a few modern surgeons and was a personal doctor to the emperor as well as chief physician for the Olympic games explicitly stated that blood did NOT move about the body. If medicine was treated the same way martial arts were, every mention of circulation would be met with "Are you smarter than Galen?" "It amazes me that people who have never operated believe they know better than Galen" and similar statements.
