Blocking T-Mobile’s last big merger turned out great for U.S. consumers. So what’s different now?

Why would the US government want to reduce competitiveness now by letting T-Mobile and Sprint merge? It’s not as if there are many up-and-coming challengers in the market — even Google’s attempts seem half-hearted. (Also, given the Department of Justice’s lawsuit against the AT&T-Time Warner merger, it’ll want to eye this deal with the same scrutiny.)

T-Mobile will make many arguments: That it’s not just competing with other mobile operators, but all sorts of internet providers; that it will speed up the launch of a new, higher-speed “5G” network, which is good for America; etc. Perhaps. But here’s one that might ring true: Despite all of T-Mobile’s innovation and growth, it’s still much smaller than AT&T and Verizon, which dominate. Even merging with Sprint — which has never really recovered from its disaster merger with Nextel in 2005, even with SoftBank’s recent attention — would keep it in third place. Meanwhile, T-Mobile and Sprint have been wasting a lot of money stealing customers from each other.Would that effort be better spent trying to take on the real industry Goliaths? Can the new T-Mobile offer even better service, with even more innovative features, at even better prices? Will John Legere keep pushing? Those are the $26 billion questions.