It seems like Angular 1.x is not going anywhere for the next three years, and here's why:
Initially, Google announced that they would only support AngularJS 1.x for about a year after the release of 2.0 in late 2015 (essentially throughout 2016), which didn't sit well with the community.
However, they later changed their stance and declared that they will continue to support version 1 as long as there is significant demand for it. This demand will be gauged based on how widely version 2 is embraced by the community in comparison to version 1 (let's say until 2017).
From what I've observed, AngularJS still dominates job postings, indicating that companies are heavily leaning towards using 1.x for new projects.
Even if Google decides to abandon the project by 2018, AngularJS remains open source, unlike Windows XP. This leaves room for others to take over the development where Google left off. In fact, even for version 1.4, Google mentioned:
"This Angular version is the first to be run by a much broader
community-oriented team, including many individuals from outside of the
Google Angular team..."
(Source: )
This indicates that Google is gradually handing over the reins of the project to the community.
There are numerous successful open-source projects thriving without Google's backing, and Angular 1.x is likely to follow suit. By the end of three years, version 2.x will be more stable, and the migration process will have been refined through testing.
If this prospect is unsettling, you could always opt for another framework, but similar challenges may arise regardless. The world of front-end development moves swiftly.