I feel like anything written in the past decade or two doesn’t really lend themselves as classic enough to be revived anytime in the future and the iconic shows are ones you can’t see closing anytime soon. For example would a revival of Mean Girls ever happen and what would that revival even look like?
I'm sure there are loads of shows that were considered very modern and topical in their day that went on to become classic and revived, whether reinvented or firmly remain in their original era. How to Succeed, Bye Bye Birdie, Sweet Charity, Hair, West Side Story are just a few. And we've had musicals set in other eras in the last 20 years that could easily become classics. I could definitely see revivals of the following:
Urinetown
Thoroughly Modern Millie
The Drowsy Chaperone
Aida (hopefully with a more cohesive production)
Beauty and the Beast
Rent
Legally Blonde
Mamma Mia
Jersey Boys
Hairspray
Billy Elliot
In the Heights
Next to Normal
Rock of Ages
The Full Monty
Ragtime
The Little Mermaid
Once
The ones I think that would be harder to revive are those that were highly dependent on the cast or original production design/direction. Shows like The Producers, Avenue Q, and Spamalot would be more difficult to revive without replicating the original productions.
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