Exactly.
Including retail I've played on 3 different servers and downed the LK on pretty much all of them. Never has this happened with a pug group. The furthest I've ever gone with a pug is Sindragosa. And that was a very, very, very, very, very long run.
Meanwhile the 10 man HC group I became a part of had no problem taking me with my ****ty 232's/245's to ICC HC as a tank. We only made it to Sindy on that first run but was about 4 hours less than that pug run. The benefit of being in a guild........
Spending so much time in a pug is ridiculous. Fair enough, I will stay through wipes, but at a certain point it is safe to say that further progress will not happen, period. Also: time invested in a guild run is an investment indeed, since your guildies learn and improve. This is also the reason that I will help some guildies out with gear/cash, it is an investment. Randoms however, not at all. Wasted time and resources.