BJJ isn't paying nothing and never payed, you need to pay to sign up to IBJJF competitions.
Today there are new competitions that are paying jiu jitsu fighters like real athletes, like EBI, Polaris, Metamoris, Submission Underground, Absolute Berkut, but they aren't even close to what mma fighters are payed.
You can't live doing jiu jitsu competitions, every top competitor has also a gym with thousands of students, do seminars around the world or has a online subscription site like MGinAction.
That's how jiu itsu fighters get their money.
Trust me, most of the top dogs in jiu jitsu today, not everybody obviously, are into mma or plan to get into mma.
Rodolfo Viera and Bruno Malfacine are full time into mma, they left jiu jitsu.
Buchecha has been years he said he plasn to do mma and will train at AKA.
Dillon Danis is signed with Bellator, Gary Tonon and Gordon Ryan just announced to start training mma and said that will be their main focus going on.
Vagner Rocha after being cut by the UFC he is collecting medals in every competition that pays money, got third at ADCC, won recently the Eddie Bravo's Combat Jiu Jitsu, but he is still active in mma.