I think Tony has the key right here:
I have trained with far to many "experienced martial artists" who can't hit me. Sure, they can score points all day long, nothing I can do to stop that. They move better, they move faster, their timing is excellent, they can set me up for whatever scoring technique they want... but I must be a Jedi when it comes to contact though. Those same individuals will pull their attacks short of delivering powerful contact by reflex. They have a very hard time when we switch the rules to medium level of contact. (no one wants a concussion, buts lets give and take some pop...) Yes they technically could have made contact, and dropped me... but getting them to make that contact is another story.
I have found that guys that have trained full to medium contact have very little issue hitting me, and making significant contact. They can dial it back, and still be in the right position, or know when they are not. They can also dial it up. Its the folks that have never trained with medium to hard contact that seem to have a mental barrier to actually hitting someone else. That can be very hard for a person to overcome.