"It sounds like you're claiming that FreeType is slower because the parsing/accumulation implementations are slower."

This is one of those performance drains across many languages that we often don't see because our weak languages don't let us. Manifesting an array for a consumer that only wants to iterate on it once, in order, with no backtracking, is a common antipattern. Just as I'd look askance at any putative "next big language" that doesn't have any sort of closure support, I look askance at "next big languages" that don't have iterators.