During ANH we see Porkins being told to eject though he doesn't do it. And in the old RPG material it talks about how rebel pilots going into battle near planets with active rebel cells are told how to contact those cells if they eject during the mission.
If Porkins had ejected, realistically, what were his chances of survival anyway? I get the impression that the Rebels really weren't in a position to mount a rescue operation- especially in the limited amount of time the pilots had before the Death Star exploded.
Ejecting on or over a planet with active rebel cells is a different story entirely, and sounds like a great hook for an adventure. My thoughts were more related to the not-uncommon scenario where a rebel force makes a hit-and-fade attack on an Imperial outpost or garrison. Even assuming that the attack is wholly successful, the limited amount of time before an overwhelming Imperial response arrives leads me to believe that it would be difficult or impossible for the rebels to recover everyone that went extravehicular.
For example, Red Squadron is a squadron of 12 X-Wings. It is currently taking part in a deep space strike mission on an Imperial listening post in the MacGuffin Sector. They know from their pre-mission briefings that from the time they arrive in-system to the time an effective Imperial response can be mounted is a full 30 minutes. Total time in hyperspace from the rebel fleet to the listening post is an hour or so, due to the multiple jumps necessary to prevent the Imperials from following them back. They expect that the amount of time it takes to deal with the Imperial forces stationed at the listening post and destroy or render the post non-functional is 25 minutes. If they take longer than 30 minutes, the sector fleet arrives and crushes Red Squadron with sheer numbers and overwhelming firepower. The situation becomes even more dire if the sector fleet possesses an Interdictor.
Now, let's say Red 11's X-Wing is severely damaged by one of the station's defending TIEs and Red 11 opts to eject rather than crash into the listening post. The rest of his wingmen are occupied with pacifying the station's defenses and completing the mission, so Red 11 has to sit tight for a little while.
Assuming the Rebels are interested in getting him back, Red Squadron can stick around and try to hold off the Sector Fleet while a recovery operation travels through hyperspace, locates Red 11, and gets him back to the fleet. This means the rebels risk losing even more X-Wings to an even larger force of TIE Fighters and capital ships. Or, the Rebels can cut their losses, change their security codes, and try to limit the damage from whatever poor Red 11 is likely to let slip during an interrogation by Imperial authorities.
It's also possible that recovery ships are sent with Red Squadron on its mission. I've never seen this supported in canon, but it is possible. This presents its own problems, because what was once a small, hit-and-fade strike mission is now a protracted engagement with an increasingly large footprint: additional fighters now must be dedicated to protecting the recovery craft.
The Empire, on the other hand, has no such difficulties. If Gamma 4 manages to eject before his TIE/Ln is destroyed, the sector fleet can begin a recovery operation as soon as they arrive. Rebel fighters will likely be too occupied by overwhelming numbers of TIE fighters (
12 11 X-Wings vs. 72+ in a single star destroyer) to attempt to interfere with the recovery operations. Even if the Empire opts to wait until all hostilities have finished before recovering its pilots, the Imperial forces won't be abandoning the area like their rebel counterparts because it's territory that they control.
It just doesn't seem like the Rebellion is in a position for much of the Galactic Civil War to recover its pilots post-hostilities. Rescuing prisoners is another story entirely, and something the Rebellion is very good at. Preventing people from becoming prisoners in the first place? Not so much. I hope that makes sense, and I am interested in hearing your thoughts on the subject.