In fact, a lot of people focus on the programming language, tools, frameworks, and what not. While the implementation is one of the pieces of the puzzle, it is far from being the crucial piece. The most important part is to understand the core concept and be able to solve problems using that concept.
You can have a resume full of various programming languages and tools. However, if you are unable to come up with solutions to the interview problems thrown at you, your knowledge of 10 such programming languages is completely useless.
As an exception, some companies working in a very specific domain indeed require you to be well versed with a particular programming language. For instance, all the high-frequency trading firms like Tower Research, APT Portfolio, Alphagrep, etc. expect you to have a firm grip on C/C++ programming since these companies almost exclusively use C/C++. Also, certain important concepts of C/C++ that are specific are often used in HFT firms. That’s why they prefer those with a deep knowledge of these programming languages.
But, by-and-large, your focus should be on learning problem-solving and building concepts than on learning 10 different programming languages.