IMHO, how many or few people pay full fare is not really the whole issue. What I see as the real issue is the fact that they are taking away the one thing that encourages loyalty to their business - Elite status. The airlines in the last 20 years have done a great job building loyalty to a brand - just see how many "My airline is better than your airline" threads there are on this site. The industry has created a situation where a sane person (I include myself in this) would pay extra and go out of their way to fly with their favorite airline versus a cheaper more convienient flight on another airline. Why do I do this? I want all my miles to count towards my status, and then my miles get doubled or whatever by status bonuses.
Perhaps someone can (and probably will) correct me, but I don't think giving people status costs the airline much money. The same money is spent on most of the extra things you become entitled to (upgrades, frist class check in etc.) no matter how many people have status - you just have more people to share it with. OK - there are some additional costs (luggage tags, employing more first class check in agents etc.), but I'm not suggesting you give status to everyone, only those who do the sufficient flying.
As a previous poster suggested, I really don't see how the restriction for elite qualfying miles/points can help a bankrupt airline.

If AA take this position (and I don't think they will), they will lose a significant amount of business from me - I won't be able to make platinum, so I won't go out of my way to fly them - my choices will be made strictly on time of flight and price.

Just my $0.02.