As you explained so well, Tolkein's work was considered not quite up to snuff, and a interesting curiosity by the "experts". HOWEVER, it actually turned out to be one of the most influential collections of prose in the past 100 years. This is so often the case that I have very little regard for the self-proclaimed experts, and what is defined as a classic. Literary experts are actually only an expert on what was. They judge something new, by how its construction compares to something old, with no regard to how it may impact and excite future authors and readers. Often, they even hold a works popularity with the masses against it. Even though it is the popularity of an author's work that can (may/will) direct the future of writing.

Oddly enough, art critics err in the opposite direction, often praising something solely because it is new, even if it has little to nothing unto itself that is praiseworthy.

Movie/play critics probably balance to two extremes the best, but it still all boils down to a person's opinion; and mine is the only opinion that is "right" for me.