Digital advertising has killed the print ad business, but not just in the hobby. Classified ads in general have migrated online.
BTW, Banacek, it was the other way round: the Village Voice was purchased some years ago by a company that owns several of alternative newsweeklies across the country. BackPage grew out of that consolidation. Eventually, pressure from various groups, including law enforcement, convinced them to split the two businesses and to relegate the hobbying ads to BP. (I've simplified the ownership story, but these are essentially the facts.)
Let's face it, if you're looking for provider ads these days, the last place you go is to the back of one of these newsweeklies. You hop online.