In my opinion it was the only good decision by Google to develop Angular2.
My first aspect is business-wise:
AngularJS had so many flaws that it would be clear that it could not compete against other front-end frameworks like React and Vue - which both got popular pretty fast - in the long term.
At the same time AngularJS was pretty much getting a "standard requirement" in job ads for front-end developers just like jQuery (of course not to that extend). So people who make decisions about frameworks, hirings and stuff already do know about AngularJS.
For decision makers it takes some time to adopt to new technologies, so they would stick to something they know, in this case AngularJS. So even if Angular(2) is technically a complete different thing, it still has its brand value and is gonna be used and - in my opinion that's important - developers will want to use it since it's a good framework that tries to remove all the flaws of AngularJS.
Another aspect I see is that frameworks like Ionic2 and NativeScript, which both depend on Angular (if you don't decide against it), are pretty popular and make developers used to develop with Angular.