Local 802 when out on Mar. 7 and struck 18 musicals.
From Workers.org. Mar.20,2003
"Broadway bosses made their union-busting intentions plain in contract talks. They wanted to abolish the union's hard-won guaranteed minimum of 24-26 live musicians for each Broadway musical. Producers wanted to cut the minimum to just six musicians.
The union said this is just the start of the theater bosses' plan to do away with live music on Broadway and replace live orchestras with pre-recorded soundtracks."
According to IBDB,
http://www.ibdb.com/season.asp?ID=1271, 2 musicals closed in the two months following the strike, "Flower Drum Song" and "Ma Rainey's Black Bottom." In the week prior to the strike "Flower" played at 56% capacity while "Rainey" played ay 55%.
The "Rainey" revival opened on Feb. 6, 2003 with Whoopie Goldberg to poor reviews.
"Drum Song" opened Oct 22, 2002 and had already posted it's notice to close.
It's safe to say the strike had no direct effect on the closings.