I think it’s dead, unfortunately. It would be a good show for maybe The Roundabout to do, but Broadway is so oversaturated with family oriented musicals right now it would be a big financial risk.
It will continue to have a long and healthy life in regional, community, and educational productions. I’m directing a high school production of it right now, actually.
If it is dead, that is so sad to me...it literally had a revival announcement, there was a lab recently, but I also wouldn't be surprised if it died either. I've always wanted to see this, it has an ok life in other markets but it's really not done all that much. Just revive it with the concert cast and it'd be fine...I think.
Warren Carlyle was recently interviewed by Ken Davenport for The Producer's Perspective Podcast. When Ken asked Warren about other projects he has coming up (besides The Music Man), he said that The Secret Garden revival is still on the table. They have a cast lined up, they're just waiting for the right theatre to be available.