What I read (maybe I've missed something) is that they feel removing tier and other significant items from LFR for 5.4 would feel like an unfair "ground rules change" to players. I get the feeling they have been mulling over loot changes in LFR for the next expansion.
But here's the thing. If LFR remains extremely popular, Blizzard will keep it around. They certainly will do NOTHING to DISCOURAGE players from using it, because many of those people will just not log on otherwise.