Business jets do have automatic descent for depressurization. But i don't know of any airliner that has that feature. Dunno why, but one reason might be the very different usage rate per year for airliners compared to business jets. We calculate with 3000 to 3500 hours a year for a narrowbody and around 6000 to 6500 a year for a widebody. From what i hear most business jets fly less than 1000 hours a year.