It's not actually the melting pot of martial arts though. It's a fight sport with open rules, that's all it is. Quit the "mixed martial arts" propaganda and see it as it really is.
Most martial artists stick to their own martial art to be honest, only a small percentage of those actually go to MMA. The majority of MMA fighters are wrestlers, guys who desperately need money (watch the ultimate fighter series you'll see a lot of that), and other dudes who just love to fight and want to make a living out of it.
MMA is a fight sport and that's what it was created for, for entertainment and money first and foremost. The other martial arts I've listed above, and there are many more, were not created for entertainment and money, they were created as martial arts with values, rituals etc.
The majority of Karateka's, Nak Muay, Judoka's, Kung Fu practisioners etc. stick to martial arts and you only see a handful of them in MMA compared to their total practitioner base.
If you don't understand why those martial arts have more values I'd suggest attending some Kararte tournaments, or Muay Thai fight nights, or Judo competitions. Then let me know once you see something like what Khabib did the other after his fight vs. Conor, or even what Conor did attacking that bus. Let me know when you find someone attacking a referee like it has happened before several times in MMA. Let me know when you see someone attack some judges after his fight like recently in Kickboxing. And I could go on like that all night.