Damage was done years ago, by the time T5 came around majority had already left. Players drifted away because of a lack of progression from new content and new gear upgrades, that goes for both dungeons and raids. We had no new raid between early 2012 and late 2014, and likewise we have had no new dungeons since mid 2013. As for PvP'ers Silirrion alienated and drove away most of them long ago.