Wrestling based with bjj purple/black belts. Your argument has no legs.
Its a huge factor because the art has to be learned to be defended. They dont teach you how to work off your back in wrestling, they teach that in Brazillian jiujitsu. The cross training is Mandatory because in MMA you end up on your back. There are no wrestlers who do not spend an incredible amount of time learning Brazillian jiujitsu if they have any aspirations of being a champion. How its used, is up to the artist. A wrestler is not going to use jiujitsu the way a jiujtisu guy will. A wrestler will use it to obtain a position he can pound on you and maybe get a head and arm triangle if its available. A bjj guy wants to end the fight and uses it for the sub. The bjj guys who use their BJJ for dominant position and striking ala Jacare, do well. When ive grappled with state wrestling champs they definately need to learn BJJ....
Also, there is a lot to be said for the genetic level of the said fighters. Roger Gracie is not an athletic specimen compared to someone like Jacare. Typically most wrestlers in mma have freakish talent as an athlete combined with their technique whereas a lot of bjj guys are built like Damien Maia and rely on technique.
There are no wrestling strikers who do not spend a ton of time learning brazillian jiujitsu. By learning it they are able to use it to their advantage/defend it but to say that by learning it, its not longer a factor or a requirment for mma makes no sense when most of the top guys have respetable belts from respectable bjj teachers.
The day of pure anyone is over but the day where wrestlers do not have to learn jiujitsu to succeed is not here. You say *o learn some takedown defense* like these training camps are just glossing over this knowledge. You're being disengenuous and showing ignorance and i believe its because of your own training regiment which doesnt include much grappling. Thats ok for joe blow and entry level fighters but if you want to train to take on dark hearted trained demonic killers, you have to expand. Take your training more serious and learn that bjj, friend.
So all of this translates to "BJJ is needed to be a well rounded fighter". Well no shyt...I addressed this, and you still have yet to address your original stance as to how BJJ is so much more important than wrestling, boxing, kickboxing, etc. For example....say if...a prime Mike Tyson entered the early UFCs....u think Royce would've closed the distance with those half assed pitter patter strikes, take him down and get the sub with ease? Doubt it. Now as far as streer fights....everyone knows that BJJ is one of the WORST arts to use in a brawl because youre vulnerable on the ground for any extended amount of time.