Several blocks of Hudson Street, between 10th and 12th streets, have been hurting recently, with 15 empty storefronts along that stretch. Local retailers offered varied explanations for the closures. Some blamed high-end Chain Stores On Nearby Bleecker Street for drawing away business. Others said small businesses had to shut down when landlords asked for higher rents. One local landlord, Alain Laurent, said he would rather keep his spaces vacant than risk having a tenant who couldn’t pay the bills.