Not quite accurate as a blanket statement. Munro did a very detailed tear down series of a sub zero refrigerator that’s very interesting. Youtube link: https://youtu.be/KAYj6m9QtDU
I wish more content like this existed. It’s the only type of review that is worth paying attention to.
Long story short if you live in an energy market like california the energy savings of the sub zero will likely offsets its additions cost over the lifetime of the unit.