I don't understand why an airline would do this. You'd be asking every airline to incur significant additional costs (on top of already slim margins for many airlines) for absolutely no tangible benefit. GPS wouldn't have kept this plane in the air, unfortunate as it is, and wouldn't have saved the lives of those onboard, God rest their souls.

If the global flying community is asking airlines to incur millions in cost I'd rather it be for something tangible that improves flight safety even more instead of something that makes it easier to find a downed plane.

This accident doesn't change the fact that there just aren't that many scenarios like this. Two in the past decade. This search is costly, sure, but it's something for which MH has insurance and can hedge against. If they had instituted something like this after AF447, it would have been a complete and total waste of money for every airline that's not MH, and it wouldn't have saved MH any money, they're still out the plane and have to bear the emotional cost on their conscience forever.