I think the exact opposite, as we discussed at The evolution of GHC - #32 by tomjaguarpaw. I am confident that Haskell usage in industry is over 10x as big as it was 10 years ago, when I started with Haskell.
But I don’t know for sure. I don’t have hard facts at my fingertips. Would you be willing to go through the Reddit archives for the last 10 years and collate all the job ads? I bet we would find massive growth!