Oh, I see. I haven't gotten around to beating G18 and starting G19 yet (I'm just catching up at the moment). It's unusual for skills to take months~years to max though. I believe some people have maxed stuff like Blacksmithing and Tailoring in less than a month just by stacking bonuses, reforges, and a massive amount of mats. There's also the fact that I haven't seen people actively running those raids...or is it because I haven't finished G19 yet?o_0
It takes at least a month to get one of the subskills. The requirements to unlock it is to do 4 weekly. Another subskill requires you to have every other subskill. Some of the subskill ranks pretty fast, some of them are mind numbing slow. Don't forget about the 40 second cooldown either.
A big issue with the raid is that it's not very rewarding. At best it lets you rank some potentially useful skills and grants you access to materials to craft average weapons. If it gave improved gold and experience, that would help tremendously.
Unfortunately, some of the daily/weekly objectives are fucking dumb.
I think this is the problem with the raids. Also, it requires a number of people to participate. Harder for some servers.
People don't see people there, so they leave. If they leave, there won't be people there. It is kind of a circle effect.