“someone whose Ayin sounds like his Aleph cannot Daven by the Amud. Who are we left with?”
I’ve never met an Ashkenazi Jew who can pronounce the Ayin.
It should be noted that English has had many pronunciation shifts over time. Jacob Grimm, one of the brothers who wrote the famous children’s fairy tales, made a major contribution to the understanding of Indo-European languages by documenting consonant shifts that distinguish Germanic languages (including English) from other Indo-European languages; most took place before the Germanic languages were written down. For example, Latin “pater” is cognate with the modern English “father”. More recently there were vowel shifts in the late middle ages that resulted in the pronunciation of English vowels being very different from other Indo-European languages; but because English was already a written language the spelling did not change. This is most easily observed by trying to read a Middle English work such as Chaucer’s “Canterbury Tales”; the rhyming clearly shows how English used to be pronounced.
By comparison, the differences in Hebrew pronunciations are much smaller even though it is a much older language than any currently-spoken Indo-European language.