You are making an unwarranted jump to conclusion. IF the Hebrew text of the Old Testament was so pristine and perfect in the eyes of the known Jewish world, tell me, why did the Apostle quote from the SEPTUAGINT so often, rather than the grand old Hebrew Scriptures???
And the only reason why Jerome liked the Hebrew was because he had this thing in his mind that something had to be written in Hebrew to be the Word of God. Thus, he changed his mind about several of the Deuterocanonicals when Hebrew versions of 1 Maccabees and Sirach were found.
Regards
Talk about a leap to a conclusion. Just what makes you think that they quoted from the Septuagint and not vice versa. What makes you think that those who were writing the Septuagint in the NT period were not quoting from the NT which they had in their possession?
Tell us --- if the Septuagint for the entire OT existed and was considered accurate by the apostles, then why don't all the NT quotes of the OT follow the Septuagint??? How come so many of them follow the Hebrew instead and not the Septuagint???
Biblical scholars indicate that only the five books of Moses composed the Septuagint and the rest of it was translated during the Christian era. And the DSS nor anyone else can provide any evidence of a pre-Christian Septuagint.