Hurricane Irene may have exited stage left by early Sunday afternoon, but Broadway shows remained shuttered for the entirety of the weekend. And while Gotham seems to have gotten off relatively unscathed, Main Stem box office certainly did not.For most shows, weekend performances generate a major chunk of a week’s revenue. The cancellation of shows on Saturday and Sunday — a two-day frame when many productions would have played three or four perfs each — is sure to cause a giant dip in the week’s receipts when B.O. is tallied today. Although the weather had largely subsided Sunday, New York City infrastructure was far from being fully recovered. With mass transit shut down since Saturday afternoon, residents were told not to expect subway, buses and commuter rails to be operating at full capacity in time for the Monday morning commute. It was the suspension of public transportation, announced Friday, that seemed to cause most legiters to sit up and take Irene seriously. Until that point, many in the industry likened the hurricane to a blizzard, a far more common local weather condition and one that almost never shuts down the Great White Way. But with transit options nixed for the weekend, it was suddenly apparent that most ticketholders — not to mention Main Stem casts and crews — would face insurmountable obstacles in getting to theaters, no matter how severe the weather proved. Productions also had other hurricane concerns to contend with, including the potential for flooding in theater basements. The sets of many shows, particularly musicals, involved automated elements that are often situated in the basement. On Sunday afternoon, there had been no word of any notable damage to Broadway venues. The theater district, located in the western midtown area of Manhattan, was not one of the low-lying neighborhoods subject to major flooding. Off Broadway productions also were shuttered for the weekend, as were all events that were part of Off Off Broadway’s New York Intl. Fringe Festival. The complete shuttering of the Rialto is a rare move for Broadway, which almost never misses a perf. Shows were darkened for two days following the Sept. 11 attacks in 2001, and perfs also were nixed due to a citywide blackout in 2003. Labor strikes halted shows for multiple perfs in 2003 and 2007. For now, Gotham’s legit industry remains on track to get back up and running today, when many shows have a day off anyway, but some — including “The Phantom of the Opera,” “Chicago” and “Mamma Mia!” — are regularly scheduled to perform.