I did not want to keep discussing these issues, but, I would like to post few questions.
1) when we I think about majority, majority of whom, - is it the same if we put all together, or a distinction needs to be made.
Natives and non natives, even scholars are the same?
2) the discussion is about "pronunciation" or προφορά, while the issue is more general, the sound of the voice given by letters composing words,
and if we want to put it in appropriate terms of the Greek grammars by the Greeks, prosody, προσῳδία,
which is the first unit that Greek grammars of the antiquity deal with,
the relationship between γράμμα - how a letter is written - στοιχεῖον - the dynamic (phonetic) characteristics of it.
3) The way that sound is pronounced cannot be learn from those who are not natives.
4) A proper understanding of the sound, gives the correct spelling,
orthophony and orthography are two sides of the same coin.
here I give the links of the greek grammars and commentaries,
Hellenism is the term used when the voice is Hellenic like,
Solacism is the syntax is not appropriate, incorrect, and therefore not clear in terms of the meaning, &
Barbarism is when the voice does not sound like Hellenic voice.
and the cholia on Theodosios discussing the above in barbarism describe situations similar to those that appear when follows a non hellenic practice.
6) Helladius in the 1712, writing in parallel Greek & Latin also takes the same position,
so if one has a hard time to understand the argument in Greek may look at the Latin parallel text.
7) Academic Honesty requires one not to refer "modern" greek pronunciation but Historical Greek Pronunciation, as Karagounis and recently Philemon Zachariou in his Reading and Pronouncing Biblical Greek: Historic Evidence of Authentic Sounds
I was recording recently a reader from a Greek Orthodox Church reading the Gospel reading.
He was confusing in his reading the ὅς as ὡς. The fact that we make mistakes, does not mean that things are the same.
From Homeric to Classical period we have the largest change in Hellenic language. Obviously, that period many things, including the sound, changed.
But from the Hellenistic period the stability is more or less given in the language, and the next drastic change is regretfully in 1981.
But even if the last 30 years many in Greece lost a lot from their understanding of our language, does not mean that all we lost our minds or our memories, or our knowledge.
The solution I propose is to go back to Byzantine Grammarians who kept the Hellenistic tradition.
[url]The Byzantine grammarians[/url] by Robert Henry Robins - 1993 - 278 pages is a good example.