I feel like, because what you really care about is how the culture has changed, you don't mind only seeing stories from every few months. It also has the effect of making the relationships feel more real and legitimate.
In too many MMOs, fate throws a bunch of disparate people together and they end up buddy-buddy almost instantly.
For the most part, in SAO you have a fairly normal meeting that doesn't really lead to any significant relationship for a few episodes. And when the times between them represent months and months, you can easily accept that.