Dak
mentat
No, I don't think it's the ultimate determinate, especially today. A canon is determined not by a small group of privileged scholars, but by the entire body of scholarship. Obviously one particularly big-name scholar could make significant headway, but a canon materializes over time and due to the prevalence of scholarship or study dedicated to particular authors/artists. And particular authors/artists generate more interest depending on how they're producing their work, what networks they help to comprise, and what kind role they serve beyond being artistic figures (do they write letters, are they editors, are they journalists, are they bloggers, do they travel, do they have other jobs, what circles do they run in, etc. etc.). So much goes into the construction of a canon, and it's way more complicated than a group of scholars sipping brandy in a Victorian library talking about their favorite books.
I'm sure it's a very well-thought out, somewhat well-defined process which has been revealed through years of dialogue and unfolding. But only the esteemed may delineate/define what dialogue is allowed and what unfolding counts, no matter how varied the "participants of the process of construction" may be. In other words, participants do not determine themselves.