Take a piece of technology like memcached which has gotten really popular in the last few years. It's an incredibly simple piece of technology really, a server with a simple protocol that allows you to set or get bytearrays by a key, and smart clients that deterministically map a key to a server. Together, you get a lineraly scaling global cache.

I've worked with web technologies for 15 years now, and I've worked with some pretty smart developers, but not smart enough to piece something like memcached together. We've done lots of different cache systems, but not as good.

But once we saw memcached, the great developers I worked with instantly got the brilliance of it, and went "Duh, why didn't I think of that?".