For the overwhelming majority of musical theater fans worldwide, the cast recording will be their first exposure to any given show. For many of them, it will be the only exposure they get to the show.
Maybe this seems obvious to you. Certainly it does to me, and yet I see far too many people consistently fail to internalize precisely what this means, which is a problem because the cast album has enormous marketing significance; and marketing, like it or not (and for the record, I broadly do not), is life or death for a work in a medium as financially tenuous as musical theater.
The Discerning Lyricist 