In practice

In practice, however, the type system constrains the programmer in many ways that are unacceptable to Lisp programmers: data cannot be interpreted as programs, lists must be homogeneous, and functions are not easily redefned without recompiling other dependent functions.

>>18
Some of those interpreters may very well be huge in code size, but they work, which means not only that it's possible, but usable.
"Usable" for what? Lisp allows to interpret code with macros. That is its use. If these were "huge in code size", Lisp would be useless.

One can even conjecture that Lisp owes its survival specifically to the fact that its programs are lists, which everyone, including me, has regarded as a disadvantage. -- John McCarthy, "Early History of Lisp"