Why stope with shows from the last few years? Hundreds of flops never got recorded: THE GIRL FROM NANTUCKET, IF THE SHOE FITS, HIT THE TRAIL, REUBEN REUBEN, CARNIVAL IN FLANDERS, COPPER AND BRASS.
It's just a fact of life. Not every flop show gets recorded, and in most cases it's a good thing.
Of the list Bryan provided, 4 are jukebox shows so the songs are available elsewhere. CRY BABY and IN MY LIFE have demo discs floating around. Only GLORY DAYS is truly gone.
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