Well, I guess anthropologist have records of these tribes. Now it is time to find the survivors and see if they want to join the rest of the world.
What, and ruin the private playground of these Anthropologists? /sarcasm
Most of these tribes have more contact than the naive anthropologist think, and have learned to avoid strangers because they end up being victims one way or another. And some tribes in the Amazon have been playing the antropologists for years.
No one ever seems to question the ethics of these anthropologists for working with governments to keep these "pet" humans for their private study, watching them die of easily preventable diseases, while refusing to offer help for fear of "contaminating" the population.
Unless I'm mistaken, the Sentinelese are the last completely isolated tribe in the world. When they say "all efforts at initiating contact have proved unsuccessful" they mean it. We don't even know what they call themselves. I guess we'll never know now..
Probably not. Everytime modern humans come in contact with these people we bring germs and kill them off.