All artists are influenced by other artists and to become an artist we need some form of training to get to where we want to go. People who claim to be self-taught usually mean their study was self-guided using museums and books and formulating their opinions and ideas without the direct influence of a teacher.
Most artists are trained by a teacher or teachers over the course of their careers. This could be at a generalized school taking art classes or a more focused approach through a trade school, academy or atelier, concentrated specifically on art. Either way the outcome depends on the student, there are far more students that graduate and have no career in art than students that are successful.
With the rise and renewed interest in realism I see a disturbing trend happening in art schools. Schools no longer train in the just fundamentals but indoctrinate students into thinking that their method is the only path to success. These schools engage in a sort of brainwashing equivalent to EST and all the other quack zealotry that happens in fringe religious groups.
A lot of schools these days prey on artists seeking knowledge, trying to convince them they must endlessly study under a school or teachers guidance to achieve success. In these situations the teachers and school are giving them only enough information and encouragement to continue forking over their hard earned money. When you feel someone is holding back information from you, find other instruction or take some time for absorption and practice of what has been learned and self-guided discovery.
Remember most academic artists at the turn of the century only studied fulltime for a year or two. Even then summers were spent painting with other students away from the instructor and school. Most of the artists of that time we revere today never completed their studies. This idea now by some institutions and teachers that you need 5 to 10 years or more of study to learn to draw is ridiculous. All a student needs is the fundamentals and some time putting them into practice on their own. Any honest teacher will tell you this.