> I can't imagine building something like a graphics framework without some subtyping.

Let me introduce you to Fudgets, an I/O and GUI framework for Haskell: https://en.wikipedia.org/wiki/Fudgets

They use higher order types to implement subtyping as a library, with combinators. For example, you can take your fudget that does not (fully) implement some functionality, wrap it into another one that does (or knows how to) implement it and have a combined fudget that fully implements what you need. Much like parsing combinators.