The high-end duopoly is real. Apple and Samsung together sold 70.8 percent of all smartphones in the US over the past three months, with "enemy of the state" Huawei down at only 0.4 percent of the US market, according to research firm Kantar Worldpanel ComTech.

Apple had 43.9 percent of US sales and Samsung 26.9 percent, according to the research firm. That's a drop of 0.5 percent for Apple year over year. While Apple is strong in the US, there are other countries where it's even stronger—iPhones made up 54.7 percent of sales in Japan, 46.5 percent in the UK, and 44.9 percent in Australia, Kantar said.

Apple is also growing fast in Germany and China, Kantar said, although it still has a ways to grow. In Germany, for instance, Android has a 74.8 percent market share.

The iPhone X clearly led to a boost in Apple's sales for the fourth quarter of 2017. During the third quarter, according to Counterpoint Research, Apple sold 33 percent of US smartphones to Samsung's 23 percent. That still totals 56 percent, but is far short of the 71 percent Kantar reported.

Kantar didn't give the third, fourth, and fifth place US finishers, but Counterpoint did, at least for the third quarter, putting LG in at 18 percent, ZTE at 12 percent, and Motorola at 5 percent.

Kantar pointed out that Huawei—which was recently described in a leaked NSA memo as so scary that the memo author wanted the government to build its own 5G network to stop it—only has 0.4 percent share here. Huawei can't find a carrier partner to sell its phones, because it's too politically controversial. But ZTE, also mentioned in the memo, has a solid and growing fourth-place position. (I speculated as to why in a column last year.)

Kantar said Motorola and Google are growing in the US, although they still both have small shares of the market: 5.6 percent and 2.8 percent, respectively.

While the Counterpoint numbers make it look like there isn't a handset duopoly in the US, read between the lines and you find that almost all of the phones being sold at the top-end are from Samsung or Apple.

Apple sells relatively few devices under $600, while fourth-place ZTE almost entirely sells budget phones. (Samsung and LG have phones at every price level.) In a November 2017 report, Fierce Wireless said Motorola had trouble competing in selling its high-end Z2 Force phone, but that its low-end, prepaid E4 phone was a success. Bay Street Research told Fierce that the high-end Google Pixel 2 didn't sell as well as the original Pixel.

While ZTE and Alcatel seem comfortable playing in the shallow end of the pool where Apple doesn't swim, things get brutal once you're directly up against the iPhone in the U.S.