Was an Angular 1 -> 2 even possible? If I remember correctly, they were one of the first big open source projects to go all in on Typescript and even the fundamental way that the rerender and state changes were tracked were completely different. I worked on an app on AngularJS and when asked for an assessment on a migration, it felt clear to me that it would require a complete rewrite. Even the tooling was totally different
That opening is what react used to become what it is today. With the 1 -> 2 no upgrade path it forced a rewrite and many left to react and never came back.