Going by that logic you should get all the loot when you destroy an invading UFO, because otherwise you would get 'punished' for having built enough air defense to avoid the base defense. You could make the same argument in regards to shot down UFOs: You should be able to recover all of the components, otherwise you're being punished because you were able to shoot it down in the first place. Logic much?
Yes. Logic much. Because you set up false equivalence. There's considerable difference between shooting UFO down as it is required to be able to salvage it if it doesn't land (in the geoscape view) and acquiring items of UFO personnel if you thin their numbers. The same there's a difference between destroying UFO on approach toward one's base to save said base and benefitting less from succesfully fended off raid because you were unable to destroy that UFO, but managed to damage it.
And certainly there's difference between any of the above and demanding all parts of every shot down UFO. If you want to ask for such, it's your right (though I doubt it'll get far). I don't and I don't plan to.
The whole point of a base defense mission is not the loot, and you're not getting 'punished' by having to fight less aliens.
Yes, you're not getting punished by fighting fewer aliens but you certainly benefit less from fending off the aliens that do attack if you were already able to eradicate intact UFO's personnel.
The point of a base defense missions is to not lose the base. Your reward is that you keep the base, and having to fight less aliens makes that easier (or for a shorter base defense mission, anyway).
No, losing a base is condition of failure. Not failing isn't whole of the reward all in itself and even if you consider it as such, it's on you. The fact is that there's still something to gain beside continuous survival from base raids and so how much is gained under what circumstances is of some importance.
