IMO, the show was twice cursed, first by COVID (as was every other show) and then by the movie. Looking back, the show was doing really well until theater shut down in March, 2020. But if my memory is right, it was grossing close to $1 million/week or close to it, and my guess is that if COVID hadn't hit, it would have had another tremendous summer at the box office.
And in my view, it wasn't so much the movie itself that hit the show hard (though it didn't help) but there was a ton if critical piling on about things like Ben looking too old (actually, he looked about the same age as all of his classmates) and a resentment that his father was a producer of the movie. In addition, many of the film critics didn't seem to understand that Evan was intended to be a conflicted character in terms of his choices. His deception started from a very good place, his desire not to inflict additional harm to Connor's family, and it spiraled downwards, out of control. I think that most theater critics understood this and far too many film critics didn't,
It leaves me to wonder how the tour is doing. My guess is that it's underperforming expectations.
CZJ at opening night party for A Little Night Music, Dec 13, 2009.