It's the opposite side of the computing spectrum. Many languages aimed at using machines, Lisp was an ideal to express computability. As other said, yeah the eval definition hides away GC, IO and the read function, which fits my interpretation (sic) of lisp as an abstraction abstraction. They weren't interested much in the machine details, this itself is already a fun fact.
So it started an ideal until a student was foolish enough to actually program it. Yet this vaporous ideal was enough to write a symbolic differentiator. You don't have bytes nor integers but you can express non trivial mathematical concepts.
You had almost nothing yet you could do a lot, another fun fact. To me Lisp is like a linguistic library, on top of which you'll add primitive types as needed. The expressiveness is given by scope, lambdas, logic and recursion, the rest is secondary. Maybe my lambda calculus classes are making me biased though. McCarthy said he wasn't too inspired by LC even though I've read he was a student of A. Church.
ps: about scoping, I've read emails from Lisp users circa 59 who were discussing the addition of lexical scope, that was before Algol was publicly released.