[AgentME]

Sometimes it's useful to see the original version of an idea: it can be easier to see what line of thought led to it, and what necessity the idea addressed. Further refinements may improve the idea, but obscure the source and original context of the idea, which might make it harder to fully understand or appreciate.

[westoncb]

The basic idea there makes sense to me, but I actually think later writers will be better at putting it into context as well, partly because they have more information on the context, and partly because the tendency when someone is first developing a new idea is to just get it working, rather than immediately analyzing where it fits in the history of ideas.

That said, I think it's definitely valuable to go back and look at original sources after starting with a more efficient, contemporary exposition.

[lefstathiou]

I believe it is worth considering also that there is an extremely strong survivorship bias taking place with these works in particular. The works of Plato, Socrates and Aristotle have survived millennia and while most works can likely be successfully summarized, over enough iterations there are bound to be a few that cannot. Reasonable people can disagree of course and this is all subjective anyway.

[agensaequivocum]

Plato can be summarized to and extent. Aristotle, however, is so concise in his language that there isn't much that could be removed. His conclusions can be summarized but one would not understand why he said what he said.