The OBC was the VERY first cast album issued on CD, the format was brand new then (1983).
At the time the standard procedure was to use the heavily compressed LP masters and release them on CD. Within a few years the 90db dynamic range of CD's was being exploited and later release and reissues took advantage of this.
LA CAGE has never been remastered, and it deserves to be. Since it was RCA's first all digital recording one can only imagine how much better it would sound IF Sony would go back to those original master tapes.
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com