O'Brien's account is generally more plausible than that of Jean-Marc Narbonne, Plotinus in Dialogue with the Gnostics (Leiden: Brill, 2011), 11-53 and 88-95 who suggests that matter is a "by-product" or "collateral damage" of the emanative
system, which exists prior to the emanation of soul.
As a clear trace of the old Greek heritage in this novel role of logos can be viewed the so-called logos-theology from the first centuries AD, which proposed to explicate, drawing on Neoplatonic models, the job of Christ as God's Word by fashioning him into a kind of secondary divine product of the emanative
chain (Young 2006:453-456).
To give one example of the complexity of the issue: Narbonne argues that the generation of matter is a "reversal of the emanative
order in Plotinus's system," because matter is prior to the sensible forms (what soul produces to cover it) in the order of emanation but posterior to them in ontological worth.
Christianity's subsequent aim of subduing the almost compulsory demand in Neoplatonism to treat the One unexceptionally in terms of absolute aloneness and not-being--which, accordingly, conferred all the emanative
being a state of gradual inferiority--, became for at least Western Christianity the touchstone for probing and elaborating its dogmatic self-consistency.
I have shown elsewhere that this emanative
causal relationship between entity and its attribute is not one of necessitation.