Non-Orthodox Jews have for decades shown three characteristics that pretty much guarantee their eventual disappearance as a people.
A very high rate of intermarriage with non-Jews.
A low birth rate, whether from Jewish or intermarried couples.
Of children from intermarried couples, a low rate of their being raised as Jews.
“Jews of no religion are much more likely to be in mixed marriages; just 21% of married Jews of no religion are married to a Jewish spouse, while 79% are married to a non-Jewish spouse.”
“Among respondents whose current, intact marriage took place in 2005 or later, 58% have a non-Jewish spouse. A similar number of those who got married between 2000 and 2004 are also in mixed marriages, as are 55% of those who got married in the late 1990s. Intermarriage rates are lower for those who have been married longer.”
http://www.pewforum.org/2013/10/01/chapter-2-intermarriage-and-other-demographics/