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Sprint took the long way to get there, but the US carrier now has recovered from years of decline, the company's overlord said Tuesday.

Sprint reported stronger financial results Tuesday, most notably the net addition of 347,000 new customers lured by network improvements and the promise of halved phone bills compared with AT&T and Verizon, the mobile goliaths. Sprint was still unprofitable, but its loss narrowed and core financial results are improving.

That led Masayoshi Son, chief executive of the Japanese firm Softbank, which acquired Sprint in 2013, to boast to reporters later Tuesday at the ARM TechCon developer conference here in Santa Clara, California.

"I think this is one of the biggest turnarounds in US history, of this significance and size," he said. "I'm very happy with the progress."

You may have thought your only real choices for phone service were Verizon and AT&T. But Sprint's recovery, combined with similar customer growth at T-Mobile, the third-largest carrier, show that the big players' leads are far from secure.

AT&T and Verizon are expanding in new directions beyond just phone service, though. Verizon is seeking to buy Yahoo, and AT&T is even more serious about offering entertainment; this weekend it announced a deal to acquire Time Warner for a whopping $85.4 billion.

Son doesn't like the idea and thinks government regulators should give AT&T a hard time -- just like they did when they blocked Softbank's attempt to acquire T-Mobile for faster growth in the US.

"The main strategy was to buy Sprint and T-Mobile at the same time so we get the critical mass to fight against AT&T and Verizon. The US government didn't accept it," Son said. He tried to sell Sprint but didn't find any buyers. "So I said now we have to fix it by itself. Now the company is turning around.

"I hear a rumor that AT&T is buying a large media company," he said. "If the government accepts that and rejects mine, I say where is the justice in this country?"