Yes there's something inherent. Namely this: the ability to drop all sorts of requirements off the table, yet still call it some kind of Lisp.

It does not need to be compiled to be a Lisp. It doesn't need arbitrary precision integers. It doesn't need hash tables. Garbage collection doesn't have to work; it can just run out of space and terminate. It can just crash on errors without a trace. It doesn't need to report the line number where a syntax error likely began. You get the picture.