tsickle doesn't look archived to me: https://github.com/angular/tsickle

Lucid Software migrated their code from closure compiler JS to typescript, and continue to use the closure compiler with advanced optimizations. See https://lucid.co/techblog/2017/11/16/converting-600k-lines-t....

It would not at all surprise me if google internally has better tooling than what they have open sourced though.