Languages like Haskell give more benefit in security/stability, testing, and refactoring. They maybe feel like they help you develop faster since they usually i

Languages like Haskell give more benefit in security/stability, testing, and refactoring. They maybe feel like they help you develop faster since they usually involve less typing, but typing isn't really the bottleneck for developing a major application. Any major project also has considerations other than code. To take the example from your other comment, there is an (open source) FPS written in Haskell, but it doesn't have the artwork, story, or level design of a modern production FPS, and someone still had to think about how to design the thing. While it depends on what you're comparing to (is the competition writing assembly by hand or writing Python in a functional style?), I don't think you'll see someone working in an advanced language getting to market shockingly faster (and their code won't run faster), or something similarly strikingly noticeable from the outside. More likely, when a company working in an advanced language does get ahead, you'll see them having a much easier time keeping up with competition and adapting to new trends due to much lower maintenance overhead. Resources expended on debugging and refactoring isn't a measure we really look at when talking about most successful projects, but it is still worth improving.