(Don't worry about off topic I love deep conversations like this. Come to our mailing list if you want to continue more though, we may be exhausting HN)
Actually, this is the type of back-and-forth I (and I think others) would love to see more of. A dozen replies in, lots of good ideas, and no one is calling anyone else an idiot or a troll. Feel free to continue!
Our compression technique is naive, you're right (but we don't decompress the whole 4MB for one single point query, as you may be thinking, we're a bit more sophisticated). We have some more ideas in the pipeline if we need them (basically a bunch of tricks you can play when you know the schema), but the fact remains that what we have right now is extremely effective and there isn't much incentive yet to finish off our smarter prototypes.