> Yes, there was a C compiler for the LISP machines from Symbolics.
Symbolics had C, Fortran, Pascal, and Prolog compilers. Scott L. Burson (on HN as ScottBurson) wrote a C compiler that ran on Symbolics and also TI and LMI machines (https://cliki.net/Zeta-C). So there were two C compilers for the Lisp machines.
So given the choice between "mainly LISP" and "LISP, C, Pascal, etc." from larger vendors that were virtually guaranteed to be around in 5 years, it was a rational choice to choose the bog-standard machines.