This is a bit far afield. The most likely prospect for G+ is that it becomes a social network for the more technically inclined while Facebook remains the social network for all -- a bit like the differentiation between reddit and digg. The main reason is not something great that Google is doing, however, but the immense dislike that many have for Facebook. Facebook, of course, is sucking in all data it can get access to regardless of whether it has any legitimate reason to take that data and, despite willful violation of data protection laws, is likely to remain above the law like many other protected parties.
I think the long term hope is that Google+ might become something like Gmail is to Outlook. G+ is the innovative, feature-driven, technologically saavy option, whereas even if more people use the "Outlook" option today, because of the technological advances attached to the "Gmail" option, people will transition to it over time.
That said, I think that is the best possible option and I don't have any reason to think that G+ is really delivering in any meaningful way on these hopes. Let's see if they actually can stay one technological step ahead of Facebook. Some better APIs would be nice...