I figure my supposes are as good as anyone elses.
If it was important, then the author would have either
(1) made his meaning clear or
(2) someone else would have also thought it was important and made his meaning clear.
That documents are not there is a pretty good clue that they are not there. When the earliest scroll is dated 200, and it is not quoted before say 140 AD, then it is tough for me to accept that it existed before that. Of course such a conclusion is tentative, and subject to being revised in the event of evidence.
What happened to the earlier scrolls or codex? The story is that Tischendorf visited the Convent of St. Catherine, and asked shelter for the night. A monk came to light a fire in his cell, and the sound of tearing was odd to Tishendorf. They were tearing up old manuscripts as kindling. Noone could read them. They had been doing it for ages.
“I here pass over in silence the interesting details of my travels—my audience with the Pope, Gregory XVI, in May, 1843—my intercourse with Cardinal Mezzofanti, that surprising and celebrated linguist—and I come to the result of my journey to the East. It was in April, 1844, that I embarked at Leghorn for Egypt. The desire which I felt to discover some precious remains of any manuscripts, more especially Biblical, of a date which would carry us back to the early times of Christianity, was realized beyond my expectations. It was at the foot of Mount Sinai, in the Convent of St. Catherine, that I discovered the pearl of all my researches. In visiting the library of the monastery, in the month of May, 1844, I perceived in the middle of the great hall a large and wide basket full of old parchments; and the librarian, who was a man of information, told me that two heaps of papers like these, mouldered by time, had been already committed to the flames. What was my surprise to find amid this heap of papers a considerable number of sheets of a copy of the Old Testament in Greek, which seemed to me to be one of the most ancient that I had ever seen. The authorities of the convent allowed me to possess myself of a third of these parchments, or about forty-three sheets, all the more readily as they were destined for the fire. But I could not get them to yield up possession of the remainder. The too lively satisfaction which I had displayed had aroused their suspicions as to the value of this manuscript. I transcribed a page of the text of Isaiah and Jeremiah, and enjoined on the monks to take religious care of all such remains which might fall in their way. “
http://rosetta.reltech.org/TC/extras/tischendorf-sinaiticus.html
This is a codex, not the older scrolls, but I suspect that the end result is the same.
Victor David Hanson wrote an article on the Battle of Salimis, in which the Greeks were widely known to have been outnumbered 6 to 1. Well they were, at least until a scroll at Pompeii, carbonized by the volcano in the 1st Century was able to be read recently using new technology (positron tomography IIRC). That scroll puts the odds at only 2 to 1. His point is that we know so darned little about ancient times. The conservative position is to know only what you have evidence on. So I use the latest possible date, as evidence of earlier dates are not there.
So now your position is the earliest manuscripts were all held at the Convent of St. Catherine?