Fear is starting to creep in as the expansion nears. Around the time we start working on Arthas (regular mode) the alpha testing of Cataclysm should be starting. Last time around this this killed raiding for the guild I was in. Things are quite different now, we won't just stop raiding when we see the changes for the next expansion, but I do believe the clock is ticking.
Rerolling, lack of interest, us having real lives and so on have prevented us from ever "finishing" the current tier of raid content before the next one was released. So far we have only finished tier 7, and I don't see us ever going back to finish tier 8 or 9.
Finishing tier 9 when it was new would have been the easiest to clear. Just five bosses and you could extend the raid ID giving you 50 shots over as many weeks as you need. We didn't get it for many reasons, the one that sticks out to me was we only had nine from our group and had to get someone on their alt to help for our 25+ wipes on heroic Anub. Now I fail as far being able to show up to every raid, I can't make next Thursdays raid for instance. My employer didn't ask me before scheduling a mandatory meeting that night.
I was working a post on gearing for heroic Arthas, but then I wondered if it was worth the effort (gearing, not the post). I guess the answer to the question "how far will we go" is as far those least interested in progression want to go. Only time will tell how far that is. I'm sure this comes off as a bit on the dramatic side for some of you out there, but it's the way I see it. That's all.