"Broadway" is defined as that which plays in a group of approximately 33 theaters in and around the Times Square area in New York. At any given time, about a fifth of those theaters stand empty, waiting for the next occupant. So at any given time, around 25 shows are playing "on Broadway."
After 8/31 when two plays (Enchanted April and the revival of Long Day's Journey Into Night) close, there will be exactly one non-musical play on Broadway — Take Me Out by Richard Greenberg. Several are scheduled to open in October but for a full month, there will be only one show running on Broadway where no one breaks into song.
I'm not sure what this means, if it even means anything. It might mean that Broadway is reaching a crisis stage in its shortage of theaters. There are a lot of shows that would like to go to Broadway but cannot find a place to play. Last year at a party, I heard a veteran of the business side of theater explain about some of the recent wars, with producers knifing one another to get this or that theater. At least one show a few years ago did a kind of reverse on the scam that Bialystock and Bloom work in The Producers. The show in question opened, did poorly and would ordinarily have closed. But its backers knew that several well-financed production companies wanted their theater and that they couldn't get it until the flop show decided to vacate…so they kept it running at a loss. In effect, they said to other producers, "How much will you pay us to close and let you have the theater for your show?" Eventually, some show was desperate enough to open before the cut-off for the Tony Awards that they paid the flop's producers enough to show a nice profit.
I believe the gent also explained that non-musical plays were at a serious disadvantage in competing for theaters. There's simply more potential profit for a theater when it houses a musical, and that may be what's causing them to dominate. Or maybe playwrights just aren't writing plays. Whatever the cause, I'll be interested to see if it keeps up.