The problem is not the availability of the music but Alexa's ability to understand names. If I tell an Echo to play, say, Zuntata, is it going to work? if I tell it japanese band names despite the overall language I speak being English or French, what will happen? Most voice assistants choke when you speak foreign-y names and can only understand them if you set the language of the device to the right language.

A voice assistant is only as useful as its ability to understand speech. If it can't tell anything from half of my music library then it's not worth much to me.

Yeah I've resigned to not being able to use voice assistants since I use 3 different languages on a daily basis.