No, but the choice of name exudes a certain arrogance that aligns with the authors of MuJoCo. It's a very capable and robust engine, but the authors have been very condescending of other technologies and confusing the terms gaming with game. It certainly won't replace PhysX as they are designed for comparatively small scale simulations, however with instancing. For instance, MuJoCo doesn't have real broadphase that scales with large environments, but sticks with the old tried-and-true SAP. Neither does it have separate friction coefficients for slip, tying it into robotics, except maybe for the VDB solver.