IMHO, no. Its easier for Google to use +1s as an indicator to measure social reach since it is their own data. Contrast this to:
 Facebook and LinkedIn: most shares/likes are private by default
 Twitter: Google would have crawl Twitter's entire corpus and tweet stream. It could do it, but Twitter's increasingly restricting access to this data.
So it makes sense from a technical perspective that Google can use only the limited information available to it in terms of social strength of an article.