I can tell you why they're not "more" famous...because they haven't released anything in 4 years. Inter Facere got a lot of underground buzz, and pretty much won over whoever heard it. Water Sphere, their chance to shine, was fantastic, well recieved, and well talked about. Then...nothing. So everything they've built up over the years and all the buzz they had has dissipated. And I'm saying this as someone who loves them and would love to hear more.
I think they aren't more famous because they're not signed to SubPop records or something similar... they self-produced everything and only had the help of GoodRecords in getting it out there, owned by members of the PolySpree. I don't think they've done any *extensive* touring, either. It is unfortunate more people don't know about their music... it's like coming across a diamond and thinking "Are you serious? No one had picked this up before I did?" You're right, though. After hearing Water Sphere, you can't help but wonder why you didn't hear about the band years ago, from everyone.
All hail Pilotdrift!