What logic is behind it exactly that says they do not lay eggs?
We have a confession from an argonion that they do sounds pretty logical to me that they do lay eggs. Also argonions are not reptiles? mmkay.
Edit: There's lots of contradicting and not a lot of lore about Argonians, but if you factor in living environment, lore and physical attributes, they dont come off as very Reptilian. Why would an Argonian have mammary glands, how could they survive in a place like Skyrim? Lots of question that make argonians seem very different from a typical Reptile.
I also think the Hist act as a dreamsleeve for the Argonians. It seems obvious when I read the novel.
The hist helps them adapt and evolve as well, I mean they are called The People of the Root after all.