I'm sure that you are aware that as far as historians and scholars, Muslims and Non-Muslims are concerned, there was never really any argument and uncertainty with regard to the preservations of the Quran, both in recitation and writing. I can provide references and sources if you like..
You have a line of reciters that have faithfully preserved the Quran. We have a line of bishops that date back to the time of the apostles that have faithfully preserved the Bible. Why doubt them? Whatâ€™s the difference?
Your claim above, however, is bogus. Here are some quotes from third party sources based on what the Bible scholar themselves stated, please check them:
"The unknown author, whom we shall continue to call Matthew for the sake of convenience, drew no only up the Gospel according to Mark but upon a large body of material (principally, sayings of Jesus) not found in Mk that corresponds, sometimes exactly, to material found also in the Gospel according to Luke. (The New American Bible, ISBN: 978-0-529-06484-4, Page 1008)"
"As for the place where the gospel was composed, a plausible suggestion is that it was Antioch, the capital of the Roman province of Syria. (The New American Bible, ISBN: 978-0-529-06484-4, Page 1009)"
"Although the book is anonymous, apart from the ancient heading "According to Mark" in manuscripts, it has traditionally been assigned to John Mark, in whose mother's house (at Jerusalem) Christians assembled. (The New American Bible, ISBN: 978-0-529-06484-4, Page 1064)"
"Although there is no direct internal evidence of authorship, it was the unanimous testimony of the early church that this Gospel was written by John Mark. (From the NIV Bible Commentary , page 1488)"
"Traditionally, the gospel is said to have been written shortly before A.D. 70 in Rome, at a time of impending persecution and when destruction loomed over Jerusalem. (The New American Bible, ISBN: 978-0-529-06484-4, Page 1064)"
"Serious doubts exists as to whether these verses belong to the Gospel of Mark. They are absent from important early manuscripts and display certain peculiarities of vocabulary, style and theological content that are unlike the rest of Mark. His Gospel probably ended at 16:8, or its original ending has been lost. (From the NIV Bible Foot Notes , page 1528)"
"This verse, which reads, "But if you do not forgive, neither will your heavenly Father forgive your transgressions," is omitted in the best manuscripts. (The New American Bible, ISBN: 978-0-529-06484-4, Page 1081)"
"This passage, termed the Longer Ending to the Marcan gospel by comparison with a much briefer conclusion found in some less important manuscripts, has traditionally been accepted as a canonical part of the gospel and was defined as such by the Council of Trent. Early citations of it by the Fathers indicate that it was composed by the second century, although vocabulary and style indicate that it was written by someone other than Mark. (The New American Bible, ISBN: 978-0-529-06484-4, Page 1088)"
snip to brevity..
Unknown authors, unknown places, unknown writings assigned to different authors, writing not in earlier manuscripts and added by unknown people/scribes etc etc..Where is that list of bishops that can be traced back to the authors? Would it matter given the above quotes??