That's not the kind of model it is. The standard model is one example of a quantum field theory. You should think of Wolfram's idea as a different formalism (ie. not QFT), not a different example. It so happens that Wolfram's multiway model (allegedly, I can't evaluate it fairly for myself) also contains GR as a low-energy limit.
It's like inventing a new operating system (we currently have 3ish, Newtonian, Quantum, and GR) instead of writing a new program (baseball, orbital motion, chemistry, gravitational waves, etc.) Perhaps new programs can be written on this new OS that couldn't be written before. If known programs cannot run on this new OS then it is defective.