[wavemode]

Typical programming style in Common Lisp is procedural, not functional.

The CL spec doesn't guarantee tail-call elimination, and most CL implementations don't guarantee it either (it could be on or off depending on the current optimization level). So most people don't bother relying on it.

[dreamcompiler]

True. My CL code is atypical because I prefer functional style to iterative style. I know how to use declarations to turn on TCO for implementations that support it, which is most of the big ones. ABCL being a notable exception.