well im brazilian and i will finally tell you guys why...
i have NO F****** IDEA!...seriously, you would think its because of the BJJ but many ppl find bjj gay in brazil, you dont know how many ppl see the mma fighters rolling on the ground and then saying ''now kiss him! har har har!''
its not because of our economy either, brazil isnt really that poor nowadays, its growing rapidly, if it was because of the economy we would see a lot of fighters from africa, central america, asia, etc.
and its not even popular, fighting and mma in general is a lot bigger in USA, Canada, Asia, hell maybe even europe, most ppl dont enjoy it, only now is the UFC starting to get popular and mainstream here
i live in curitiba, you would think that there would be many mma fans since here is where chute boxe lives, and shoguns new gym UDL
but not many ppl in curitiba enjoy mma also...i simply dont understand where the hell all these fighters come from or where they live
I'm brazilian too, living in Florianópolis. I am a MMA amateur fighter myself, started at taekwondo (2o dan today) and I am a BJJ black belt too. I prefer to compete in IMAS (Integrity Martial arts System, like MMA, but no GnP, only BJJ on the ground) only because I don't live for fighting ( I am an economist) and I have to preserv myself. MMA is really not very popular here like it is in Asia, US and Europe, I don't have any reason to believe economics aspects have any correlation with that, you don't have to have that many resources to be a good fighter. My opinions on why there are so many brazilians in MMA are:
1) We just like fighting in general! We tend to be very proud too, that helps.
2) For us is very useful to know how to defend ourselves, because we eventually have to use it.
3) I practice martial arts since I can remember, I know many fighters and martial artists , and here in Brazil there is a tendency to practice several martial arts or disciplines in the same gym, for instance, in my TKD gym, we have BJJ and Wrestling too (only here we call it greco-roman fighting). Most of us are versed in BJJ and Judo, even the ones dedicated almost exclusivly to TKD, and I know in other gyms the pattern is the same ( BJJ, MT, Boxing).
4) Finally, Gracie's legacy may seem to attract brazilian BJJ fighters to MMA, but actually BJJ fighters prefer to fight in submission or BJJ tournaments rather than in MMA nowadays.