>>I honestly doub tthe same thing can be said for someone who's much more familiar with writing formulae than writing complete sentences.
There are no such people. With the immense intellectual effort that it takes to grasp today's cutting-edge physics it is implicit that one masters mundanities like writting.
The existence of savants who at excel mathematics or physics but can hardly pull their pants up is a popular myth, but a myth nonetheless. There are autists who can do amazingly quick calculations, but I assure you, none of them know category theory or QFT.
So why isn't there more sci-fi written by scientists? Because it's a waste of their time.