So, it's still an expanding market - or maybe just a volatile one! This is also true of the Australian classifieds sites I've been listing. There's never a shortage of ones I've never seen before.
Of course, some of these directories will go kaput in time. But there'll always be new ones. That's why I'd urge anyone who has a business to keep doing various keyword searches across all the major search engines and submit your site to a few from time to time. (And if you can, try to be wary of shonks. Google for reviews of sites if you have time. Unfortunately some directories are run by scammers who do charge businesses for listings they never asked for.)