I would never suggest that retaining or recovering a magazine should take higher priority than staying alive. But I would suggest that retaining your mags (Especially when you don't have a military to issue/resupply more) is a priority to maintaining your combat effectiveness, and maintaining combat effectiveness, is a priority to staying alive.
I do understand your point though, and as I think I said earlier, there are certainly times when I do NOT retain my mags, a true emergency reload would be one of those times I suppose. In truth, I practice mag changes a lot (like, rifle empty, new mag in, hit bolt release, rock and roll) but I haven't actually practiced a true "Emergency Reload" (where as a result of a FTF you physically have to manipulate the bolt) more than 10-20 times.
I will definitely try some more drills that involve ditching them right away and see how much faster I can get. For the most part however, unless the scenario requires the utmost speed, I will continue to train to retain my mags, there part of my rifle.