The problem with the 'all scripture is inspired' bit, is which scripture did that particular writer mean? Was a letter from 'Paul' considered scripture as soon as he wrote it? One wouldn't have thought so. And when Paul was supposedly doing the apostolic thing it's very likely much of the rest of what was later decided was to form the NT canon hadn't been written either, let alone been formalised into a canon of any sort. That came about much later.
So, no, that scripture proves only that early Christians hadn't rejected what came to form the OT.
This is 101 stuff Perry. Ehrman's point is that there are thousands of differences between manuscripts for the NT. The vast bulk of those are minor, many just scribal errors. But some are quite significant. And there is ample evidence for the early Christian church being quite open to revising what they had received, not to mention adding to it further with even later writings. Paul's writings actually set the standard for this - his whole claim to being an apostle was in a divine revelation to him personally. Others clearly felt they too had been similarly chosen out in such a way. Who gets to decide which of them is right? Ehrman is quite right in saying, this is the part preceding what you quoted, that it's a fairly modern definition of being a Christian to accept that the bible is infallible. As he points out in the article you quote, there's nothing about this being a doctrinal necessity in any early christian statements of faith.