I think yes and no. Yes in the sense that the raw physiques that are the best suited for a specific sport aren't so rare as to where Lebron James is literally the only person on the planet with his combination of strength/speed/size. There are and will be other athletes of comparable (and even superior) physical makeup. But no in the sense that every 'greatest of all time' caliber player ever tends to have involvement with the game at a very early age + advanced coaching at a very early age + a well traveled road to follow from an early age.

For every Serge Ibaka or Yao Ming that shows up with immense physical gifts from an unlikely corner of the world and who takes on the challenge of developing their skills to become world class and vital to their team there are also your DJ Mbengas who find their way into the league in no small part due to their amazing physicality and athleticism only to never really become a focal point of their team.

Similarly you get players like Lamar Odom who had damn near every 'perfect' natural basketball advantage a person could possibly ask for, even arguably more so than Lebron and he grew up playing the sport and he was in and around leagues and coaches his whole life but the peak of his career was being a 'just really good 6th man' and never even came close to approaching the next level of star/superstar status.

But overall, yes. The potential is out there, hidden across billions of people and every franchise commits no small amount of effort towards trying to find it. Personally, I suspect as international basketball continues to become more popular we'll not only start to see more obscure talents popping up from unexpected places but even potentially getting to a point where the best player in the world might not even be playing in the NBA.