People will just remember, re-enact a bit here and there but it will never be quite the same.
See Joplin, Hendrix, The Doors, The Beatles (it was VERY short lived but people still talk about it re-enact it etc), Abba.
I actually think a lot of "the legacy" is already in the past. In 50 years time people will still talk about Bat but doubt many will talk about HCTB. The musical might have some legs but there is no way of knowing till a few years down the line. It may only last a year or two. Love Never Dies people already don't care about. People have also pretty much already forgotten about Whistle Down the Wind and considering the two names involved that is surprising too. There are only so many things artists and auteurs get remembered for in the long run. Most people will remember George Lucas for Star Wars but won't give a crap about THX1138 or the Ewok adventure movies. etc... Fans will know and still collect it all and that's ok too.
