The fundamental theories are good enough in that we can't find a counterexample, but they're only useful up to a certain scale before the computational power needed is infeasible. We're still hoping to find higher-level emergent theories to describe larger systems. By analogy, in principle you could use Newton's laws of motion (1685) to predict what a gas in a room is going to do, or how fluid will flow in a pipe, but in practice it's intractable and we prefer to use the higher-level language of fluid mechanics: the ideal gas law, the navier-stokes equations, etc.