What you don't see is the hundreds of poor street vendors doing this exactly the same all over Rome. This is not talent, they have to do this, they are from families and areas under control of the mafia and doing this is the only way they can pay their rackets.
That is true, I went to Rome, saw that amazing paint and gave the person money and applauses. I kept walking and saw hundreds of people doing the same and thought that... I couldn't sleep for at least 1 hour thinking about that.