JennH said: "phantom4ever, I love how we both used the term "negate" 
blaxx-Ok I get that, sounds like it was a "necessary evil to accommodate the best of both worlds" scenario. I can imagine a sound tech back then just wanting to teartheir hair out constantly, but with how far sound tech has come since then, wouldn't there be way around this now, 30+ years later? I also recall agood fewyears back, the show was dark for about a week to make way for a new sound system.Apart from that, that cadenza is indeed tricky to do that many times a week, even specifically opera trained singers will confirm that, but it's doable a few times a week. Justhave a recording ready in case on a given day it's not. Without having to sing it, there really is no need for an alternate. Of course Iwouldn't complain about getting paid the same, whether I was the primary or alternate 
And it's certainly no secret that all the phantom's offstage stuff is pre-recorded, but that actually makes sense to thestory itselfbecause of the idea that all those years as a circus freak show attraction, he learned to throw his voice, hence adding to the eerie mystery of the whole thing as well as himself.
drybandit- Sure, but there's plenty of other roles that are on stage just as much as she is, PLUS arguablyhavemore singing to doand they don't have alternates. Elphaba anyone? That roleis another that's overdue to have one. For the past decade or so, the standby has goneon often enoughto call for this promotion change.Evan H didn't have one at first, but now he does, which is necessary since they startedcasting actual teenagers.It's not so much how much stage time you have, it's what one is having to do during that time. I think Jekyll/Hyde didn't start off with one, but ended up getting one, though I've never been able to confirm this, because ifnot, that's another role that 100% needed one. It's pretty god forsaken."
^ You're spot on. Elphaba (and Glinda, for that matter) don't have alternates but they do have stand-bys. Christine doesn't. She doesn't sing the title song but there's still Think of Me, All I Ask of You, Wishing You Were Somehow Here Again, the Final Lair, walking with those heavy costumes...