On the one hand, Guilds can feel like families - you know the vast majority of the people reasonably well, you do stuff with them on a regular basis, you help them out (if not all, then at least some). You want to get along, you don't want to be the cause of friction and cause a drama fest.

On the other hand, members can take advantage of this situation (on purpose, or through sheer ignorance because no one's asking them to do other wise), and the higher ups are afraid to rock the boat by becoming demanding or think their only recourse is to completely gut the guild, rather than actually performing the role of being an Officer, or anywhere higher up in the usual hierarchy.

It's the Officers' responsibility to push the guild; it's not the Officers' responsibility to bend over backward to serve the guildies and do things so the other guild members don't have to expend effort.

A foundering guild is not due to "bad" general members.

As others have said, if the guild in generally isn't putting forth the effort they ought to be, let it be known that their raiding spot isn't reserved just for them because they're part of the guild. They get their raiding spots when they earn them. And if they're not earning them? Officers need to do their part to make the choice to have those not bothering to exert effort sit out, and replace them with someone more capable.

If there's no real penalty for under performing, there's no reason to work harder and focus.

If they're still not up to par, it may be time to have a word with them. Ask them why, and whether they feel their goals meet those of the guild. If they do not, discuss with fellow officers whether it's time (on a case by case basis) to ask that member to leave.

My guild has very specific requirements for members, one of them being, "Attend at least one guild raid a week on a regular basis; if you can't do that, we may have to ask you to leave. We'll be happy to invite you back when you're available again in the future." We've had perhaps 1 instance of some drama about a year ago, and that's it.