The problem is, there are logistical considerations on an airplane. Reports coming back from these incidents in the air are that there was only space for one or two people in addition to the FA (if that), not to mention that other customers still have to use the bathroom and want their snacks and drinks, etc., so you can't clog up the aisle on a plane with multiple people indefinitely. Also, as said before, for most inflight emergencies, death isn't something that's likely to happen (only two thirds of one percent of the time) so it's usually more someone who's not feeling well, and that could be for a variety of reasons.