The bit about "Canon, Sony, and Nikon may have replaced Kodak for professionals" was entertainingly silly. AFAICT, Kodak cameras were never used by a significant fraction of professional photographers? (maybe pre-WW2?)

Film is a different matter of course.

FWIW, Canon, Sony, and Nikon all make sensors as well as cameras (I believe Nikon just tweak Sony's these days, but they were certainly making their own at one point).