Of the top long running shows, LES MISERABLES, CHORUS LINE, MY FAIR LADY and OKLAHOMA! are deserving of their critical and financial rewards. CATS, GREASE, PHANTOM are not.
I would not consider any of the current crop of new musicals entirely successful articically or financially. In the last 10 years only one musical was as good as the critics said: RAGTIME - but it was not a financial success.
Only time will tell but I doubt in 50 years PHANTOM OF THE OPERA will be anything more than a footnote: it will be too expensive to produce with all the speactacle and pontless to produce without it.
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