I only really joined a progressing FC within the last week - and I had gotten up to Binding Coil Turn 4 on my own. Mostly through DF or PF, no voice chat. It just takes a lot longer.

For instance, I was joining PF group for Titan HM to get my WHM relic for about 2 weeks, several hours a night, almost every night, before I got in a group that could actually beat it. If you're playing casually, that could stretch into months if you're unlucky. But that's really the ONLY fight in the game so far that is horribly difficult without a FC.