How many players have remained anymore that actually raid? The 25man guilds that can do heroic can be browsed in a matter of seconds on wowprogress. Only in a couple of clicks you see all 13/13hc and you go to the pits of hell of 4/13 normal and you see people being 2000th in the world!
Wat? I remember a couple of years ago being 4000th and having 4 or 6 heroics to reach it.
In contrast the 10mans are tons. The 13/13hc are billions compared to 25s but they still offer more actual guilds that raid.
I suspect 25man bosses are nerfed to accomodate the few remaining WoW players and they STILL can't manage a lot.