Out of that list, Mr. Roxy, I think we can only expect to see Barnum again. Mind you, I really like all of the shows you mentioned, but:
Li'l Abner has a lot of 50s topical humor and Cold War paranoia worked into its script, plus entire generations have grown up not knowing the original comic strip and the title means little to them.
Irma la Douce, I've been told, hasn't worked well divorced from the original expressionistic Peter Brook production that surrounded it. I love the score (and that rambunctious overture!) and think that with a charismatic star, it would work, but I don't expect to see it hitting the boards any time soon.
Applause could possibly work, but the score has a few clinkers, ("Fasten Your Seat Belts," "Hurry Back" among them) and that very 70s sound that would need a tune-up. And it failed quite spectacularly in that recent Stephanie Powers tour that closed on the road.
Golden Boy is unearthed every few years, between the Long Wharf production and the recent Encores production, and always seems to fail to rise to the occasion, despite that lovely score.
Barnum has a paper thin book, but it really doesn't matter. It's a terrific entertainment, a marathon central role, a fabulous Cy Coleman score and audiences love it. I think it will receive a mounting in the next few years, if the right star comes along. (Wouldn't Hugh Jackman be something as Barnum?)
"Gif me the cobra jool!"