You have to wonder why The Singles 1969-1973 keeps getting released on all these new formats. You would assume that As Time Goes By might get a release
That's no mystery - it's because The Singles is a megaselling hits album, and As Time Goes By is more of a curiosity that only major fans have seen or heard of.
It always seems that when reissued, the "mega selling" albums of an artist's career continue to be the best sellers, even if their whole catalog is reissued. People don't "discover" a great old album in droves, they still just buy the Greatest Hits record. (Unfortunately.)