Well... chances are you've made thousands of phone calls through switches running Erlang. You may have used Emacs, Discord, Facebook, Pinterest, Spotify, Font Awesome, xmonad or visited web sites running Elm or an Elixir backend... or even driven a Volvo.

Here's a list of companies using Haskell, with similar links to other functional languages: https://github.com/erkmos/haskell-companies. It includes names like Facebook, Tesla, Klarna, Target and Kaspersky.

Not to mention the FP paradigms used in Python, C++ and other languages. In fact, if you've never come across FP "in the wild doing something" then I suspect you're living very much off-grid.