Universe needs not be made of elementary components, in the way in which computations are.

Moreover, all computational models assume some sort of global state and absolute time. These assumptions don't seem to hold in physics, or at least they may hold for a single observer, but may require complex models that don't respect a natural simplicity prior.

If it were possible to realize a Solomonoff inductor in our universe I would it expect it to be able to learn, but it might not be necessarily optimal.