I've been fascinated with this topic for some time now, almost to the point of obsession. After researching the issue for several years, I have come to a conclusion/theory that I would love to receive some feedback on. This theory of mine is one that will be somewhat unsettling to both those who believe the divine name was used in the original NT scripts as well as those who believe it wasn't. Here goes:
It is true, as the WT frequently mentions, that the earliest Septuagint fragments prior to, during and even after the 1st century contain the divine name in some form of the tetragram (or in some cases, the greek IAO, whatever that was!). Therefore, it is certainly reasonable to believe that the greek texts that Jesus, his apostles and the early Christian congregations were familiar with did have some form of the name in it. However, if, as the WT concludes, the NT writers continued this Jewish practice (using tetragram in the NT greek), then it is also reasonable to believe that they continued the Jewish practice of NOT pronouncing the name when they came across it in the text. This would explain why later copyists of the NT (as well as the Sept.), most of whom at this later time were Gentiles, would simply render "Kyrios" (something familiar to them) as they believed that this was the Greek equivalent (or at least one of them) of the "strange" Hebrew word, YHWH. I feel this is a more satisfying explanation as opposed to the melodramatic WT belief that the name was removed because of some Trinitarian conspiracy (keep in mind that-and this is something that is strangely absent from most discussions on this controversy-there was no real equivalent of the divine name in Greek or any other language outside of Hebrew, since, other than some abbreviated forms such as "IAO" or "Alleluia" the Jewish scribes did not fully translate it)
I know this topic has been covered previously, but I am new to this forum and would love to hear anyone's thoughts on my conclusions, as I feel it is a sort of "third-way" explanation. I am open to any constructive critique!