Does teaching Buddhism work? Why did the Buddha bother to teach? Why does anyone teach today? Is there evidence (a charged word) or scriptural support that it really does any good? I read here many things that accord with my experience, but it also seems to "multiply entities" and so we wind up with lots of words when perhaps fewer would be better. Perhaps it would be more effective to simply have places of teaching, and those who wish to know would go there. A friend was saying to me recently that describing advanced experiences or ideas to family or friends only makes them think that one is deranged, it does not "light the way" for them if they are not looking.
To use your own analogy, if you were trying to learn how to implement an OO design pattern in JavaScript, would it be more expedient for you to try and figure it out for yourself or to learn it from someone who had already mastered the concept?  Buddhism can be a very technical religion.  There are some problems that will arise (and meditation alone is chock full of them) that you just won't be able to get past without someone there to guide you along.  What's worse, sometimes you don't even know what questions you should even be asking!  You might be doing something totally wrong, but without a teacher there to point it out, you'd never be the wiser.  You likewise might master somethings, but not know where to turn your attention next.  

I don't think the importance of a teacher can be overstated.  One of the qualities of the Buddha is that he is an anuttaro purisadammasarathi - an unsurpassed teacher of persons to be tamed!  That wouldn't be in the Buddhanussati Gatha if it wasn't important!