Inferno JS is probably one of the newest "frameworks"/large-libraries that I would even consider using, and it's over a year old already.
React has been around in some fashion since 2011, and was open sourced in 2013.
Angular 1 has been since around 2010 IIRC. Angular 2 since around mid-late 2015.
Ember since before mid 2014.
Yes, some terrible developers like to chase the "new cool thing" every few weeks, but that doesn't mean that you need to, and it doesn't mean that there aren't stable, powerful, good choices that have been around for years.
