I'm rather skeptical of this. Perhaps because I live somewhere where there's only 3 different carriers and they all started capping mobile internet in the same month. And they all dramatically raised prices in the same month. Etc. For now, you're able to buy a vanilla Android phone from a third party, but what happens when carriers start to only allow IMEIs sold through them or their subsidiaries on their networks? Carriers have way too much power right now, partly because Google caved in and allowed them to butcher Android phones.
We need to be vigilant as a lot of consumers don't really care about these kinds of things.
I'm not the most knowledgeable within mobile geekery, but couldn't you in buy an android phone with no contract over the net and get a sim card for it?
The point regarding IMEIs was that if carriers get antagonistic enough, it would be possible to change the blacklist that (some) carriers use for stolen phones into a whitelist that disallows any third party phones.
Outside the US, governments take the promise of being able to take a SIM and put it into an unlocked phone very seriously, so I'd say this is a strictly local problem. In fact, I'd wonder how Deutsche Telekom's regulators would react if T-Mobile (DT's US subsidiary, at least for now) started doing something like this (that they probably wouldn't permit in Germany).
We need to be vigilant as a lot of consumers don't really care about these kinds of things.