The simplest answer (which I seem never to give!) is just about how the business operates. Network / cable channel programmers rarely sit creating new shows or brainstorming about what shows to revive.
Creators, producers and rights-holders pitch shows to the networks. So, for example, the only way "Name That Tune" would be revived would be if the present owner of the format, Phil Gurin, were to make the overture, pitch, dance, buy dinner and politic for it. Rarely would a network or cable channel call around to ask "Hey, who owns 'All Star Wait Until You Have Kids', we want to revive it".
Mark Itkin at William Morris would have to make calls and drum up interest for "Supermarket Sweep" to be revived. A hundred Al Howards sitting at a hundred telephones might sit for a hundred years waiting for an incoming call to start the ball in motion.
Sometimes successful producers can "leverage" their success with one show to get another show added or revived on a network they are doing business with. Goodson-Todman was adept at that tactic.
As most of the formats worthy of a revival are now owned by one of a very small handful of companies it is safe to assume that the development people at those companies ask themselves regularly about what properties might be ripe for a re-tooling, and for which potential buyer. Like "How about a fun, party-like reincarnation of "Match Game" for someone like FOX?" ;-)
Randy
tvrandywest.com