A number of stars of that "Golden" era Mary Martin, Carol Channing, John Raitt and Alfred Drake seldom missed performances. Gwen Verdon missed some of REDHEAD due to an injury and began cutting songs at matinees of SWEET CHARITY.
The myth persists that Ethel Merman never left a show and never missed a performance. She did leave ANYTHING GOES before it closed to go to Hollywood to make the (very unfaithful) film version. She left PANAMA HATTIE (she was pregnant) as well. She rarely missed shows, usually only because of illness so severe she could not sing.
Once in GYPSY she burst a blood vessel in her throat and was out for a week. Buy she had a level of professionalism that few current stars maintain. She felt that since people had paid good money buying tickets in advance to see her she had an obligation to be there.
In an interview years ago she said "I also gave the same performance closing night as I did on opening night...I cannot bear to have people let down on the job...you have a contract and you should live up to it!"
This nonsense that some stars have in their contracts that they only have to show up for 6 performances a week should be forbidden. If you can't handle 8 performances a week 50 weeks a year, then stay away from Broadway.
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