I imagine the time discrepancies between normal solves are so low due to the simple fact that cubeshape + OBL can be inspected at the beginning of the solve (of course, only by world-class solvers), which spans half the steps. Combine this with what is effectively an entirely algorithm-based solution, and blazing fast times suddenly seem far less superhuman.
By no means am I discounting how well they did, they are incredible solvers with immense amounts of skill and dedication. Onya boys!