"Leading" I don't think is misleading at all. In terms of numbers and integration I think Qualcomm is ahead of nVidia, TI and Samsung the main other silicon vendors to high-end phones, although the likes of Broadcom, Mediatek are catching up.
Additionally since the context of the leading comment is in reference to Intel competing with Qualcomm it seems very appropriate since the Atom based phone chips Intel is pushing are targeted towards Android currently (and presumably WinPhone in the future) which correspond to Qualcomm's Snapdragon lines, not it's lower end chipsets.
I'm also not sure that it's true to say that Qualcomm locks-in manufacturers. Long standing Qualcomm customers such as Samsung, LG, Motorola and HTC are all releasing phones and tablets using chips from other silicon vendors. I think they are seeing multi-sourcing as a way to extract greater value from their suppliers be it Qualcomm or anyone else - suppliers always tend to be more responsive when they're not a sole supplier.
I'm also not sure that the changes to the ARM core in Snapdragon really affect software standard compilers (such as gcc) produce code that works just fine on Snapdragon - in fact gcc is the compiler of choice for the Android project which is where a lot of the Snapdragon processors are used.
Where there are differences is in peripheral integration due to Qualcomm following an SoC approach (which is also being pursued by Broadcom and Mediatek). This tends to mean that Qualcomm designs lag, some silicon vendors, in terms of headline grabbing figures and number (e.g. number of cores), but as a result tend to use less power and space due to the integration.
And of course the modem is on the SoC which is a both a major advantage (since there's no integration work for the manufacturer to do) but that is somewhat of a lock-in but pre-qualification means that switching modems is not as difficult as it might be.
And I do not think "Leading" is misleading - Qualcomm have been shipping 100 million chips per quarter for the last few quarters - I do think that probably qualifies them as leading. I tried to find out what Mediatek have been doing and they're numbers look to be in the 10million a quarter. Also Strategy Analytics estimated Qualcomm's market share of smartphones as 44 per cent and the largest individual (though it was down from 51 per cent).
Overall I think this shows a healthy market. There is no one company that has total dominance so competition is leading to better products from all players at keener prices.