Question about running the Cabin AC while traveling

I think somebody asked in this thread... At least in theory, the "dash air" in a typical vehicle approaches 20,000 btU. Call it "ton and a half." I recall discussing the capacity of automotive A/C compressors and if recall's working some were rated 22,000. That's a LOT (I refuse to imply a pun and say "a ton") of A/C, but automotive wants quick cooling that can overcome lots of heat absorption from glass and metal, along with losses to the air while moving.