Rhetorical or not, it's not the kind of question that calls for a sincere answer. Anyone asking a question like that has already decided they know what their answer is, and there's nothing anyone else, especially not a stranger, can say to change their mind.

So Krouse might as well call this a rhetorical answer.

"Because there's only so many hours in the day, unless you know something about time I don't." A little resigned, but mostly tired. "Prioritization. It's a lifesaver."

An observation as trite as anything Deku has said so far. He's pretty sure by now that Deku is one of the types who thinks trying harder is a substitute for practically any lack of time, resources, or information. There's no helping people like that, even if he wanted to.