Sorry for your loss of players. It happens. I have played Warcraft since day one. I have played TOR since week 1. I have seen guilds gold and fall and good players leave for reasons. Firstly, the game continues regardless. Secondly, it’s not your fault. Folks left for reasons to get Traya from other guilds. Yes it sucks, but it’s their choice. Regardless of how well you think you are treating them or fair you are, people bail on life long friends for personal gains. It’s no different than if Apple dangled $$ at Google employees to entice them to work for Apple, which does happen even at the company level. Just using them as examples, not testifying to their actual business practices.
Don’t take it hard or personal. Just keep playing for enjoyment and foster esprit de corps with what’s left of your guild and rebuild with new blood. It’s painful, but, again freedom of choice which you have no crontrol over.