Origen says Marcionite manuscripts were burned the the orthodox.https://books.google.com/books?id=Ie7CD ... AHoECAgQKQ The same was true under Constantine and beyond. So yes if you're expecting 'the manuscripts which survived' to be a level playing field in any theological question yes, I think you willing accept ridiculous arguments to honor your ancestors. It's a ridiculous ridiculous - borderline disingenuous - to make this appeal in a discussion such as this.I want to establish that one point, at the very least. Do you agree that the extant manuscripts offer no support for your theory?
To answer your question - the scribes were copying previous MSS. I am sure that by the fourth century they read the MSS the way you suggest. Although we should be careful at assuming that information did not pass along. For instance, I read an AMAZING discussion of Nonnus's preservation of Secret Mark https://brill.com/previewpdf/book/edcol ... 25_015.xml. Utterly brilliant. But how long did people wrestle with Secret Mark until Konstantinos Spanoudakis effectively proved its authenticity? Again the ancestor argument is hard to break.