Yeah, code search is a niche market numerically speaking, but intellectually and economically (considering the economic impact of software) it is vital. Google was doing so much better a job of it than anybody else that they completely owned the space. How could that not be worth what it cost them to run it? And now we are bereft of anything good.
I used to use Google Code Search like this: encounter an unfamiliar language or API construct, go to code search, get page after page of real-world usages. Or like this: wonder how to do X, imagine what code that does X might say, search for snippets of that until hitting a working example of X. It was a powerful learning device that I am sad to lose. I sure hope a startup comes along to get search right for the world's source code. Github ought to, but their search sucks.
In any case, congratulations Russ Cox et. al. on a brilliant piece of work.