[harimau777]

A traditional martial artist who has seriously trained in sparring would also be able to deal with an unskilled fighter fairly easily.

The difficulty arises when the rules of a sport cause a fighter to ignore situations that can arise in an actual fight. For example, I train in Dog Brothers Martial Arts. Grappling is common and encouraged, but at the same time most fighters conceal training knives on their person and headbutts are common. That requires an adapted form of BJJ from that used in MMA. Overhooks become more valuable because they allow you to control a limb that is holding a weapon. When you are in the bottom of guard you need to keep your opponent away from you so that they can't headbutt you.

[Silhouette]

Yes, this is the sort of distinction I had in mind when I commented before that MMA is still a sport and for "real" fighting you might choose to add other types of training as well. The possible presence of weapons is one huge difference. The open environment where you don't have an octagon wall to limit your opponent's movement and a conveniently flat floor is another.