“There’s hardly anything surprising about the 2007 Pulitzer going last week to David Lindsay-Abaire’s Rabbit Hole. But the award is yet another sign that this isn’t the most welcoming of times for envelope-pushing drama. Broadway is rife with revivals and British imports. And the big regional theaters, established as an alternative to the commercial system, have had a tough time staying true to their mandate. Risk-averse programming that favors the familiar, preferably with a star lead, slick showmanship and a clobbering marketing campaign, isn’t limited to the Great White Way.”