I think the Speed Force was something they pulled up as an afterthought, to explain how all his physics-breaking basically-magic powers worked. Hell depending on the story Flash can also time-travel, phase through walls, permanently immobilize people, all by manipulating speed.
I always wondered how speed super power works.
If everything becomes a blur to him, he wouldn't have enough reflexes to avoid crashing everytime.
But if his reflexes match with his superspeed, then to the person it would feel like a boring very long run in normal time.
