The QWERTY champion

"For years, I've been the QWERTY champion within Sprint," Kaufman began.

"Sprint's had one of the largest bases of QWERTY going back to the whole messaging phenomenon ... at one point we were selling 40-percent messaging phones," he explained right off the bat.

When Android came along and smartphones truly began to take off, handsets with QWERTY keyboards did very well for Sprint. The Samsung Moment, the EVO Shift, the Epic 4G: "We sold multimillions of those," said Kaufman.

"It was a big party and nobody came."

All the research told Sprint that it was on the right track, that physical keyboards were a differentiator that would help the carrier sell phones. When Sprint conducted surveys, it found that 70 to 80 percent of respondents with side-sliding physical QWERTY keyboards reported that it was easy to type words and letters. By contrast, touchscreen-only devices typically polled under 50 percent.

"The best [touch-only device] we ever had was the Galaxy Note II," said Kaufman, on which 54 percent of respondents said typing was easy. "The iPhone 5 was around 48 percent, just to give you a sense."

And for a time, it seemed like that typing experience would actually drive future purchases. When Sprint asked customers whether they'd buy a physical keyboard the next time around — not so long ago — 75 percent of existing QWERTY users said they would. Even one quarter of iPhone users, and 30 percent of Galaxy Note II users, said they'd prefer a physical QWERTY keyboard on their next smartphone.

"So we had all that data, and we said 'Look, there's still the demand for QWERTY.' And then we went out and built the LG Mach and the Photon Q."

"It was a big party and nobody came." So much for surveys.

What happened? People started buying phones they could recognize, according to Kaufman. He believes the reason that QWERTY phones stopped selling has little to do with large screens and everything to do with a trend towards "iconic" handsets: flagship devices which boast fancy designs and giant advertising campaigns.

"At the end of the day, what happened is two things. Half of your customers buy the iPhone. All those people who said, "Oh, I'm going to buy QWERTY," boom, take them out of the equation."

"And then as you probably know, the market has moved to everyone buying iconic phones... people see the advertising, they walk in, they want to buy a Galaxy S III," says Kaufman. "Or an HTC One," he adds suddenly.