I've been playing the game of Go for 15 years. I barely know how to play Chess beyond moving the pieces. They are both board games played on a grid. I should be a pro at Chess based on my Go experience?
Haskell isn't completely different from your standard imperative programming language (functions, variables, etc), but it is definitely a different enough paradigm that you can't just pick it up in a day or two based on your existing experience. My biggest struggle when I picked it up 4 years ago was unlearning my imperative knowledge. Once I was able to throw away my initial preconceptions things got easier.
On the other hand, software engineering is still software engineering. Regardless of what tools you use, you usually have to solve them in a similar way. Your 15 years are still useful :)
Haskell isn't completely different from your standard imperative programming language (functions, variables, etc), but it is definitely a different enough paradigm that you can't just pick it up in a day or two based on your existing experience. My biggest struggle when I picked it up 4 years ago was unlearning my imperative knowledge. Once I was able to throw away my initial preconceptions things got easier.
On the other hand, software engineering is still software engineering. Regardless of what tools you use, you usually have to solve them in a similar way. Your 15 years are still useful :)