As someone who has contributed to this problem of inactivity in KoS I thought it might help to share my perspective.
Long Story Short: Perhaps it is different on the Empire side (and it's a shame we have to be in two separate silos in the first place), but I just never got the same vibe that I felt during my pre-SWTOR days in Stonewall on STO.
Long Story:
I mostly played Republic, and during my time the really active people I teamed up the most (who were former STO friends, happened to be on at the same times, had toons around the same level, were always fun to be around (not uptight), welcoming, regularly doing flashpoints/instances etc.) decided to separate themselves from KoS. Regardless of why, the ripple effect was that it made things kind of awkward for me because I didn't really have any other KoS friends to fall back on that were around my same level. So-to-speak, the rug was "force-pulled" from under my feet.
Personally, I prefer to be part of a larger guild (like Stonewall) where you can have your "clique" or the folks you regularly play with, but then there are enough other guildies around to help fill empty slots in teams, which in turn helps to build new relationships. While it's noble to start a new guild, unless everyone lives in the same time zone and has the same schedule it gets lonely pretty fast. While we have our share of drama, Stonewall is still a collection of the most level-headed, generous and kind gamers I have ever met (even the folks I'm not personal friends with). I tried to get to know folks in other gay guilds like Rough Trade but frankly I found the people there to be too vulgar and/or mean (and for those of you who know me, it takes a lot for me to think something crosses the line). In other words, Stonewall is still the best.
There were a few reasons why I quit the game:
I was noticing that a lot of folks I befriended one week would be gone the next regardless of it was due to "drama," cancelling their "sub," technical issues etc. It got old investing time/energy getting to know someone only for them to disappear. To be frank, I want to play a game to have fun, not feel depressed. Some games playing alone is ok, but SWTOR is not one of those games IMO.
Coincidentally around the same time I just got tired with SWTOR. Zep pretty much nailed it; I was just one of those people where the novelty wore off. While all MMO's are repetitive, I raised my JK to 40-something and I just lost interest in seeing it through to the end because every mission felt the same and it started to really bug me that bad guys just stand around in a field. Sure, I could start another character class, but without other friends around to do missions with I didn't see much of a point.
I also didn't like the physiological effect that paying a subscription fee does to me. I feel that I have to play as much as possible to get the most out of my $15. And then if I didn't feel completely satisfied with my gaming experience then the money was wasted. At least with being a lifer on STO I can play in whatever short spurts I want without feeling I left money on the table (I have more than received my money's worth).
It also didn't help that I started playing Skyrim. Playing with myself has never felt better (that statement came out wrong, maybe I'll come back and edit it later ;) ). I've probably put in 100 hours and am still finding new/interesting things to do at my own pace. And then once I'm done with that game I have Mass Effect 3 to look forward to. Long story short, I have been enjoying my "offline" time.
Just to throw in my two cents to the issue at hand: I wouldn't hate the players, hate the game. If there isn't anything going on or other people around willing to team up then what is the incentive to stick around? While I may have a deep loyalty to Stonewall and have no plans to change my allegiance, at $15/month it is asking quite a lot for folks to wait around hoping things will improve. That's too high of a price I'm willing to pay considering the alternatives that are available to me. I doubt I'm the only person who feels that way.