It's almost as if Tegra is always unlucky, either with delays or some other issues. This time what stopped Tegra 3 from completely taking over the market (other than the Qualcomm S4 chip) is the ability to integrate the LTE chip inside the SoC, which offers some benefits like lower cost for the buyer, lower time spent on integrating it, and it's more energy efficient.
Since Tegra 3 didn't have this, that means that opened up the market for Qualcomm's S4 chip, which is not only more powerful in some (most?) situations than Tegra 3, but it also comes with integrated LTE. Some of the more popular devices like the Transformer Pad Infinity, Asus Padfone, AT&T HTC One X have already moved to Qualcomm's S4, and this should only cause other manufacturers to do the same.
Perhaps Tegra 3 is only saved (a little) by the fact that Qualcomm has so much demand that they can't satisfy all their customers' needs, so Tegra 3 can fight for some newer popular devices that can't get S4 anymore, at least until the Tegra 3+ arrives. Nvidia is really milking the Cortex A9 chip design with Tegra 3+, because they should've had a Cortex A15 version by then.
By Q4 even Samsung will have Cortex A15 chips, and Nvidia probably won't have a Cortex A15 chip until Q2 2013. Leaks have shown that they have a quad core 2 Ghz Cortex A15, which should compete with Qualcomm's quad core S4 design, and Samsung's Exynos 5450. If this year still doesn't make it clear who makes the most powerful chips, perhaps next year that will be revealed to us. [Via AndroidCommunity]