Comment by philiplu
No, there were two devs working on the 68k Mac compiler, with ~10 devs on the x86 side (though both targets shared a lot of code and differed mainly in the late codegen and peephole optimization phases). I never worked on the 16-bit code; the 32-bit and later 64-bit x86 backend was a different codebase from the 16-bit stuff.
Any idea how many devs are working at Microsoft on the C and C++ compilers these days? I've heard rumours that there's more on the Rust team and that C++ is taking a back seat.