Indentation-sensitivity seemed like a great idea in 1983. I'm not convinced today.
Personally I think it causes more problems in interpreted languages, a lot of those disappear with a compiler with thoughtful error messages like Scala.
Surely neither OCaml nor Haskell are in the top 20 of any "Most Used Programming Languages" list.
I will give you that for highly specialized domains, those lists would look different (eg in some niche OCaml would be high while Rust would be low, or R high where C++ is lower down the list) , but it is telling that Scala comes in at #32 when compared to other languages that, I think, occupy a similar problem space.
Of course, Python is #1 on the TIOBE list (and have had a strong showing for years), which I ascribe to the overall productivity and wide application domain fit. So, whether or not white space is objectively bad (for any language or only some languages), it hasn’t detracted so much from Python’s popularity.
But also C# has indentation-sensitivity. Otherwise multi-line strings would not work.
I could imagine that other popular languages copied or will copy the same trick as C# does.