I agree with the insight brought forth here , but let me throw something into this , perhaps the confidence goes both ways,. By this I mean ,when a project or a part is " offered" to an established actor ,She/He has an immediate advantage ,in that He /She knows /feels that receptiveness ,that flows from the auditors like a waterfall ,therefore making it easier to bring forth thier unique offering of talent with conidence and the freedom to explore ,expand and create freely ,thats where the real magic is unearthed ! However Versus the up and coming talent,that may not be afforded that mutual confidence by thier collaborators. As an actor one hopes that the collaborators are there to ...with thier artistic contribution to ,bring forth the ,Underground well spring of talent .Perhaps ,in other words the actor is but one part of the total artistic creation ,the director holds the celluloid paintbrush ,so to speak . Of course there has to be at least a potential " diamond in the rough " with the talent auditoning , but there also must be a confidence and freedom on the directors part ,to bring forth a new and unique creation .however in this " thing of Ours " we know all too well it is Buisness , and taking chances and having confidence in a virtual unkown is risky ! So have that confidence and freedom ,and if you start with the potential right collaborators , the finished Diamond ,may shine as bright or brighter than what has been cut before . In short it is mutual confidence akin to knowing you have a great partner enhancing and building on what you are doing in any given circumstance ,i.e. knowing someone has your back so to speak . All this being said ,for the most part I feel that receptiveness with auditors in general , but at the end of the day in reality , most will take the safe way home