The disco days are dead, that much is certain. No more brokers driving Mercedes, no more crane skyline, no more developments popping up around the desert like toast from a toaster. Construction and real estate, Southern Nevada’s second most important industry, have crashed, and there likely will be little building here for several years. Start with the bad: All those half-empty neighborhoods on the edge of town become exurban ghettoes. These neighborhoods share the worst aspects of suburban life.