First of all, we have a clear focus: increased privacy.
Second, it's not only about the mobile OS, it's also about associated web services. Who would care about a new mobile OS if he used Google services everywhere?
Last but not the least, in my opinion the common point of failure for all these projects is: LACK OF APPLICATIONS. But as eelo is forked from Android sources, it will be able to run any mainstream app. (read https://www.indidea.org/gael/blog/leaving-apple-google-eelo-odyssey-part1-mobile-os/ if you want to know more about this important point)