Not surprisingly, many of those Samsung users (31 percent of all Pixel 3 buyers) were coming from the Galaxy S7, a device roughly two years old. Counterpoint also found that 14 percent of Pixel 3 buyers were coming from Motorola handsets, while 15 percent of OnePlus' shoppers previously used LG devices.

These aren't completely shocking figures. Both handsets are potentially better value for money than Samsung's phones, and in some ways are considered polar opposites -- they aren't saddled with as much software bloat, and typically enjoy timelier OS updates. Still, Counterpoint believes this could be a "disappointment," particularly to Google. The company has long positioned the Pixel line as an iPhone alternative, but 82 percent of its customers are already using Android. It's not so much expanding Android's reach as it is poaching sales from its own partners.