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There are lots of good reasons to create specialized languages for hard problems. http://en.wikipedia.org/wiki/Domain-specific_language and http://www.paulgraham.com/onlisp.html both address this. Google has lots of people who are capable of creating those languages, who faced hard problems to solve that hadn't been tackled on the same scale elsewhere. Sometimes they wrote languages, and some of those have been widely adopted internally.

If the language is well-suited to the task, this is in fact an efficient approach.

http://en.wikipedia.org/wiki/Sawzall_(programming_language)

Most of the "great" languages were at one time internal to a company or research group.

http://golang.org/

That one actually seems more supply-driven than demand-driven. Google hires huge piles of accomplished people, and the senior ones then continue to work on whatever it is that they do, because they're well-known and independent enough that it's hard to assign them to projects they don't want to work on. So they hire Rob Pike and Ken Thompson, and the result is a programming language inspired by C and Limbo, because that's what they do. =]