The argument in favor of the merger is that T-Mobile can't leverage its existing network into a competitive 5g network, but Dish can create a competitive 5g net

The argument in favor of the merger is that T-Mobile can't leverage its existing network into a competitive 5g network, but Dish can create a competitive 5g network from scratch. How are these both true at the same time? All the MVNO operators I know of are on Sprint and T-Mobile so that's not real competition. Dish may or may not follow through. So it's definitely a loss of competition for 7 years in the hopes that Dish gets us back to where we started with 4 operators... What are the odds this goes well for customers?