I think when you say "make Android builds faster", you mean "make Android application builds faster" -- as opposed to making Android operating system builds faster. Those are two very different things, and for the uninitiated the casual use of language here is confusing. The Android operating system has never been built with ant, but historically was built with make until around Android N when that team started migrating to ninja-based builds instead.
I got confused by the exact same language 5 years ago when one of the Apache Groovy project managers (before it joined the ASF) started repeatedly saying "Google have now chosen Groovy and Gradle for building Android." I didn't know if they meant building Android at Google, or as the default build system shipping with their (then) new Android Studio tool.
