Lots of people here are bashing Kung fu and various ancient martial arts. The thing is, I am going to prove why you don't see legendary warriors in the UFC step by step:
1. Often times, many MMA fighters train and fight in order to fulfill their narcissism and to validate their self-worth as well as pride while others like Conor and Floyd fight for money.
While legendary martial arts masters train to become an absolute master of their particular art form/technique. Their training is more in depth and has a stronger degree of concentration as well as depth and in doing so, they train their body and mind outside of civilization so they can not be corrupted by outside influence and have the ability to become one with nature.
2. MMA fighters train what they are told that works, they are simply followers of the modern trend of their combat sports. They are way too obsessed with praise and compliments due to ego and so simply train accepted methods in order to please their overlords which can be trainers/fans/promoters etc...
Meanwhile, legendary martial arts masters explore the subtly and nuances of their style and they train with absolute concentration. They wont even let their inner voice sway them with distraction, if they are working on mastering their strikes be it kick,palm,punch,knee etc... they do so with reverence like a saint giving worship to their god/universe. The legendary martial artist trains their strikes with reverence and utmost sincerity.
3. Lastly, MMA fighters are tied down by distractions and shitty lifestyle. In order to become a master of anything, you need pure concentration, focus and abstaining from anything that diminishes your passion or energy levels.
What this means is, MMA fighters LOVE to party, drink and do drugs as well as looking for random hook ups and getting tatted up and always looking for validation. Like the saying, it takes energy to be a rock star. While that's true, this energy can be applied to learning new technique or recovery method. This behavior causes scattered mindedness.
While legendary martial artist usually spend time trying to understand the nature of life by mediating in seclusion, they practice chi kung, tai chi and this clean lifestyle relaxes the nerves and allows faster recovery and better focus of mind.
Also, legit ancient martial artist are flexible like a yoga master and they practice dynamic tension and various forms of weight training like stone lifting and they don't need to deal with the drama of having a shitty promoter talk shit about them. They have self-respect!
EDIT:
I am not trolling or being a comedian. I saw the other thread and I am defending Kung Fu. Speaking of long term development, this is what Kung Fu can do for you:
See, no goofy Mcdojo master, legit kung fu masters are in great shape even in advance age. This guy is doing Iron wire, a southern kungfu version of the dynamic tension.