I read it all ack-ack, and I do recall the specific part you are talking about. One of his best liked rear gunners drowned in a river they tried to swim across. However, if I recall correctly (been awhile since I read the book) there were other occasions he mentions where he landed to pick up downed pilots or he detailed one of his other pilots to land and pick them up, he just went into less detail because those instances were less eventful. (for such a remarkable pilot, his book is very thin on descriptive details) So yes, you are right that on that occasion he landed and got stuck in the soft mud and was unable to even start rolling again (even after taking off the dust guards for the wheels), but that one failure doesn't mean it was never done successfully.
gyrene - yup there is already a good deal of squeaking, whining, and armchair generaling (btw, that last phrase felt as stupid to type as it is to read, sorry about that) and of course a rescue feature would create more but hell, there are people out there whining right now about the latest feature/update (GV changes) and there was plenty of whining about the ones before that. Unfortunately it will always be a part of the game. But you also have to look at the up side to it. wouldn't a lot people at least like to have the opportunity to be rescued rather than captured? (I know there have been a few times that I would have liked to call up a squad member on vox for a ride back to base) And I am sure there would be players/squads that would make a name for themselves as good rescue pilots "sweet! pilot xyz is on our country tonight! he almost always responds to rescue requests." much like there are people out there who see a 262 cutting through a furball and downing planes on almost every pass and think "*%#&, I bet that is Grizz in the 262 coming at me" or the respect people show the 91st HBG when they put together one of their large missions, respect from both sides of the mission. There is already a number of people (yes me included) who will drive/fly GV supplies out to a downed vehicle to "rescue" that driver from a ditch landing or a death landing. The way I see it, this wouldn't be all that much different in principle.
aaaaand, end wall-o-text