Such profound hostility to the performing practice of the received tradition made the sanitisation of Byzantine chant a fundamental prerequisite for its acceptance and consumption by Westerners and Westernised Greeks. Conscious emulation of the Solesmes restoration was, as we have already indicated, a particularly ingenious solution to this problem. Adoption of the earliest manuscripts as the sole arbiters of authenticity and without grounding them in a developed concept of performing practice meant that Tillyard, Wellesz, and Høeg were able to bypass entirely the embarrassing “nasal singing” of traditional Greek cantors in favour of a hypothetical reconstruction that was both aurally and methodologically fashionable. With everything distasteful thus reassuringly dismissed as “Arabo-Turkish” accretions, its new Western curators could ensure that Byzantine music “in all its original purity” assumed its rightful place alongside Gregorian chant in the pantheon of European musical history. (Alexander Lingas, “Performance Practice and the Politics of Transcribing Byzantine Chant”, Acta Musicae Byzantinae VI, Iaşi, Romania, December 2003, p. 74)
Full article is here. It’s a barnburner, and tells you not only what Lingas thinks of the “narrative of decline” but also what Greek chant specialists thought of it while it was initially being promulgated in the first place. (A tip of the hat to Basil Crow, who passed this along.)
Leitourgeia kai Qurbana: Contra den Zeitgeist 
What’s interesting about this theory of decline is that it is, itself, thoroughly Hellenistic, in that it assumes a Greek origin of chant, and completely ignores the entire Middle East — ironic, since Christianity was born in the Middle East, not Greece or Byzantium.
I’m consistently amazed that despite academia’s realization and acceptance of the errors of the so-called First Generation Byzantine Musicologists (Wellesz, Tillyard, Strunk), public perception has not followed suit and remains mired in such absurd suppositions such as the “corruption” of Byzantine music during Ottoman times. This is exemplified in the PBS special and the Antiochian priest’s article you referenced in a prior post.
The fact is, this is an academic battle that was won by scholars a generation prior to Lingas, although he summarizes succinctly above what the issues are and what the first scholars’ limitations (and biases) were. However, it’s indication that much work remains to be done in “popular” thought amongst current Orthodox laity and priests.
Thanks for linking Alex’s article.
I guess it just goes to show — it ain’t what you don’t know that gets you into trouble, it’s what you do know that just ain’t so.