It seems Qualcomm's S4 chip got so popular that they can barely make enough of them, not just right now, or until a couple of months later, but they have it booked until the end of the year. Qualcomm was already the market share leader in the mobile chip market, as they've been doing this earlier than pretty much anybody, and they pushed strong with Android early on with the first 1 Ghz Snapdragon processor.
The S4, which is also the first to make the transition to an architecture significantly newer and more powerful than Cortex A9, before the arrival of Cortex A15, is also giving them a nice lead in the market for next-gen devices. Qualcomm says that out of 370 total design wins, 150 of them are only for S4. That's astounding. That means 150 different phone models will have the S4 chip inside in the coming year or so.
The first Cortex A15 processor should come out mid-summer or early fall, and it will most likely be more powerful than the current S4, so Qualcomm will have to offer something better. The more obvious way would be to increase the clock speed to 2.5 Ghz per core as soon as possible (by mid-fall), but I fear Qualcomm now believes you need a quad core to compete as well, so they will probably push their quad core 1.5 Ghz S4 Pro in fall instead. That's unfortunate because just like people recognize that a dual core S4 is more powerful than a Tegra 3 right now, they will also recognize that a dual core 2 Ghz Cortex A15 is more powerful than a quad core 1.5 Ghz S4 Pro chip.
Hopefully, Qualcomm will still want to sell a dual core version in fall, and they will realize that the way to continue to compete is to increase the clock speed of their S4 chip, and pair it up with Adreno 320.