Last spring, in the early days of Broadway’s Covid-19 pandemic shutdown, news reports and industry chatter referred to an eventual (and, it seemed, imminent) reopening as if a light switch would be flipped and the marquees of all 41 theaters would light up the Midtown night. Actors had left their dressing rooms full of the usual personal stuff — street clothes, photos, charms — as if they’d soon be back from a long holiday weekend.