Jailbreaking should be compared to "rooting" in android world. And only fraction of users who rooted their phone install CyanogenMod.

What do other users, who rooted their phone? I, for example, installed OpenVPN. I had to have "su" access in order to do that. But I do not plan to install CyanogenMod any time soon simply because of lack of the time.

So... 1 million of Cyanogen users is pretty significant number in fact.