No reason huh?
Some "scholar" comes up with a POV and it winds up in a million books.
Luke never met Jesus, he was the "physician." Probably in the Ministry. He
collated accounts and read documents and wrote Gospel of Luke. He gave
us the history of the first church, up to the beginnings of the persecutions.
His account ends suddenly when he was in Rome with Paul, ca 66.
John was Jesus favorite disciple. He wasn't an intellectual man, didn't
know or care much about the history or the law. He wrote Gospel of John.
We read the same writer in John's epistles.
Matthew was an educated, rich man. He was a tax collector and knew
the law. His writing Gospel of Matthew shows his legal shorthand.
Mark I haven't looked into. Don't think much is written of Mark. Must
check.
None of the epistles or Gospels make any mention of the Roman war.
That started same time as Paul and Peter were killed in Rome.
Mark: "The writer does not identify himself in he gospel text, and scholars, unable to verify the late second-century tradition of Markan authorship, regard the work as anonymous."
Stephen Harris, The New Testament: A Student's Introduction, 4th edition, P. 119
To all intents and purposes we must study the Gospel as if it were anonymous, like most of the books of the Bible -- a "traditional book," that is, a book basedon a common tradition, not a product of personal literary authorship. There is a decided advantage in this: the Gospel is far more broadly and securely based if it rests upon a widespread social tradition than if one individual's recollections … provide the sole support."
ed. Geroge A. Buttrick, The Interpreter's Bible, Vol. 7, P. 632
The last chapter indicates that the gospel genre is not that of an eyewitness account, because the gospel was probably not written by Matthew, on e of the twelve disciples. The apologetic nature and late date of these claims, the gopel's likely date of origin in the 80s, and its use of Mark as a source indicate that such a designation is inappropriate."
Warren Carter, Matthew: Storyteller, Interpreter, Evangelist, P. 30
"As in Mark's case, the author does not identify himself, suggesting to most historians that the Gospel originated and circulated anonymously. The tradition that the author is the "publican" … mentioned in Matthew … dates from the late second century CE and cannot be verified. The main problem with accepting Matthew's authorship is that the writer relies heavily on Mark as a source. It is extremely unlikely that one of the original Twelve would depend on the work of Mark, who was not an eyewitness to the events he describes.
Date: the 80's CE, at least a decade after the destruction of Jerusalem."
Stephen Harris, Pp. 148,149, 152
"The question is hotly debated whether the attribution of this Gospel to Luke is accurate information or a secondary development resulting from the early church's desire to attribute the Gospels either to apostles or followers of apostles. This question cannot be answered with certainty."
Robert Tannehill, Luke, Pp. 20-21
"...Scholars think it unlikely that [the author] was an intimate of [Paul]. Luke-Acts is anonymous.
Date: about 85-90 CE, significantly after the destruction of Jerusalem and the church's transformation into a primarily Gentile movement."
Stephen Harris, P. 179
You see, it's not just "some 'scholar.'" It's the consensus of recognized, peer-reviewed, bible scholars. I don't know where you're getting your information -- you don't cite your sources, but it's certainly not in the mainstream of biblical scholasticism.