The bloat is not about the size (sbcl and ecl can be pretty slim for what they do), it's the spec.

To write down the full spec, you have to document everything in those hundreds of megabytes. That's going to run for thousands of pages.

If your spec is small but you have hundreds of megabytes of bloat, it means you're not even remotely documenting everything.

You are really wrong. The Common Lisp Hyperspecs weights very little in my machine. 2.2 MB compressed as a TGZ.

It's really docummented. But the standard compared to Scheme it's huge.

PD: 2.2MB as HTML text weights nothing. You don't need images. It's 16MB uncompressed. More than 1500 items. People often forgets how little plain text weights.