ὡς ἔπος γὰρ εἰπεῖν ὀλίγου αὐτῶν ἅπαντες οἱ παρόντες
ἂν βέλτιον ἔλεγον περὶ ὧν αὐτοὶ ἐπεποιήκεσαν.
Does Socrates speak of himself? That he could have spoken better than them about (gen. part. here*)
one work of that which they themselves had created? Then how come the object of comparison is also in the nominative here?
And if he talks about them, that they could have spoken about their own creations better, then how does αὐτῶν fit here?
* my commentary.
EDIT: So after checking the 1966 translation @ Perseus, I understand that Socrates had separated the crowd and the poets,
and that he speaks of the crowd in ἅπαντες οἱ παρόντες and the poets in αὐτῶν.