Boy, the implementors made a significant mistake in this one. Though CLICC is not intended to be a complete Lisp system, but a Lisp application, they insisted that CLICC has to itself be a CLICC-compiled application. And so what that means is that, then, programs being compiled with this bootstrapped CLICC are severely limited as to what they can do at compile time (in macros), simply because of the crippled run-time environment of the CLICC-compiled CLICC compiler which has to run without the benefit of an actual CL runtime. Whereas if CLICC had been kept as a Lisp-compiled program, only the run-time parts of user code would be restricted to the "CL1" language; macros could be written in full CL.
> Why not Racket or Common Lisp etc?
These already have solutions in the compilation space.
Kyoto Common Lisp (KCL), a fairly old implementation tracing back to the 1980's, and its descendant GNU Common Lisp (GCL) compile to C.
Embeddable Common Lisp (ECL) also contains a Lisp to C compiler.
Of course, numerous CL implementations compile to native code without the C route.