I disagree. I'd say all training is like a simulator. Some is better than others. It really depends on what application you're specifically talking about.
A pro-MMA fighter is an expert MMA fighter. He is analogous to an expert pilot in this area. When you get into fighting on the street, he's like a guy who has a professional level simulator. The transition from fighting in a cage to fighting on the street isn't far, and someone who has developed a lot of skill in the former will likely be able to transfer the skills to the latter.
This is true for all martial artists who have a means of applying their skills. Judoka, Kyokushin Karate, TKD. These guys are all developing real skill. The question is, how applicable are those skills to self defense? But in every case, there is a gap. The key is that, because there's application, the gap is known.
Now, things get really dicey when you don't even apply your own style. You end up moving another step further away. For example, a guy who trains Aikido and practices skills against a "resisting" opponent in class is never actually applying the skills. Rather than becoming an expert Aikidoka, he's becoming an expert Aikido Student. And what's the result? Well, we see it whenever we see an expert aikido student try to apply the skills against someone other than another expert aikido student. It never goes well. And it's here where you really run into people who don't know what they can and can't actually do.