> Why doesn't C# have anything like C++'s <algorithm>, or Rust's composable iterators, or Haskell's plethora of composable abstractions (foldables, traversables, lenses, etc.)?

I'm not very familiar with the details of Rust iterators yet, but there isn't much I'm missing from Linq at least yet (apart from the cost control available in Rust and C++ that it's pretty natural is omitted from C# where it's natural that operations such as iteration can heap allocate).

What is the difference between <algorithms> and the similar Linq (or rather the enumerable extensions enabling linq)?