As Qimmik noted, ἐπιθυμήσειεν is 3rd sg. opt. and it would be reasonable to assume τίς is its
interrogative subject. The sentence ends with ; which is the Greek conventional question-mark.
From what I understand, the gist of the sentence is Socrates' statement that people who already
possess certain physical attributes, still wish to possess these attributes. But, he asks, who would desire
to have what is already in his/her grasp?
According to R.G. Bury
, the paragraph leading to 200c, is about wanting and desiring pertaining
to the future -- keeping/maintaining what we now possess --, not to the present.
I struggle to explain δήπου here. This question does not, as stated in Smyth 2850
and is often the case, expects a positive answer. Its sole purpose is to oppose any such notion
that these people's desires pertain to the present. Harold N. Fowler (Cambridge, 1925)
as "and how, I ask, is a man going to desire that?" He then immediately inserted "No" for the following
ἀλλ᾽ ὅταν τις...