Joel Spolsky, writing about Netscape almsot 15 years ago:
When you throw away code and start from scratch, you are throwing away all that knowledge. All those collected bug fixes. Years of programming work.
You are throwing away your market leadership. You are giving a gift of two or three years to your competitors, and believe me, that is a long time in software years.
You are putting yourself in an extremely dangerous position where you will be shipping an old version of the code for several years, completely unable to make any strategic changes or react to new features that the market demands, because you don’t have shippable code. You might as well just close for business for the duration.
Not only is Angular 2.0 a complete rewrite, they anncounced the death of 1.x a year before 2.0 will even be ready. This seems like a really terrible idea.