> I understand your point if you are speaking in literal terms about just simple cons cells, but in practical Lisp/Scheme code, you don’t really rely on just the basics to do things.

Agreed.

> So what about streams? Functions? Closures? Call/cc structures?

Those are interesting examples. They are all data structures in a sense (especially streams and closures), but to me they are more like functions than data (yes, yes, functions are values, blah, blah). Call/cc is a reification of execution control; thinking of it in terms of data stretches my brain.