Let's grant (which we shouldn't) that the distinction between a philosopher and a non-philosopher is as sharp and as clear as could be. Philosophers grasp the Forms; non-philosophers don't. Philosophers have genuine virtue; non-philosophers lack virtue entirely. Let's accept the picture of the Phaedo that Bobonich wishes to draw part and parcel.
But so far we are talking about philosophers and non-philosophers 'in a state of nature', so to speak, or as private persons living in some larger society.
Now suppose, however, a relationship of authority between these two classes: philosophers have authority, and non-philosophers live under their authority. Even more, suppose that the non-philosophers recognize:
- that the philosophers know something that they don't;
- that knowing this is important for achieving human welfare;
- that the philosophers, in their authority, genuinely aim at the good of those under their authority.
Now what do we say about the virtue, or lack of virtue, of the non-philosophers? Certainly the non-philosophers will act in virtuous ways. Certainly too there will be reasons why they act as they do--which they recognize, even if they don't grasp them themselves. Call this sort of virtuous-like behavior 'participated' virtue (following traditional Platonic usage) .
That is, take the view of the Phaedo, introduce a structure of authority as described, and then pose the question: Given this adjusment, would Plato speak of the virtue of the non-philosophers as he speaks of the virtue of citizens in the Laws? That's the crucial question, I think. If the answer is 'yes', then no change between the dialogues; if the answer is 'no', then change.
But there is nothing in the Phaedo to decide this, and therefore no basis for claiming that the view of the Phaedo is different. (If anything, 1.-4. of the previous post indicate that Plato would be inclined at least to regard participated virtue as in some sense virtue.)