Yeah, Brazil has turned out some awfully good fighters. And with good reason.
Brazil had people mixing Muay Thai, Jiu-Jitsu, wrestling, and boxing back in like the 30's or 40's. We're talking almost half of a century before it started getting any serious attention here in the USA, and it only got serious attention here because some Brazilians started up something called the "UFC".
Now, the Brazilians who started up the UFC weren't so much MMA dudes, they were pretty anal about just being Jiu-Jitsu dudes. But there were (and are) a lot of other fighters down there who were just as good, and had a wider blend of skills. And because Brazil is a freaking rough place, these weren't rich kids taking martial arts classes a few times a week, they were real bad-A dudes. The stories, including invading rival dojos, street fights, and a whole lot of butt-kicking, are things of legend.
Why does America have so many great fighters? I think it's just because we're rich enough as a society that a lot of folks can afford to spend a considerable amount of time and money on things like fighting. Just an average monthly dojo fee here is more than most of the families in the world *earn* in a month.
Japan's big, because they've been doing martial arts since way back. No history lesson needed. Those guys DIG their fighting, and the appreciate it for the skill of the fighting itself, not just to see somebody get knocked out. One of the Pride events had the world record for highest viewership, over 90% of Japanese households were tuned in for it. I dunno why they aren't more successful than they are, though. You would think that a country like that would completely dominate.
Anyway, very few Americans - even big MMA fans - really know anything about the history of MMA before UFC 1. But that's because most of the pre-UFC MMA history was all in Brazil.