Catching the last two hours of VH1’s five-hour series 100 Greatest Kid Stars the other night — namely No. 40 (Todd Bridges) through No. 1 (Todd’s co-star, Gary Coleman) — it was suddenly apparent how TV has moved cute child stars out of evenings and into the niche world of 24-hour kid-friendly cable channels. There was a time when Coleman, Emmanuel Lewis, Ricky Schroder, Melissa Gilbert, Miyam Byalik, etc. were big names on par with their fully grown colleagues on other shows, almost giving the impression the networks did have a “family” of stars. On VH1’s show, Lewis (No. 6) boasts about how he was personally assured he’d get his own sitcom by the head of ABC, based solely on his popularity in commercials, as if he were the “get” of the season. But now that more aggressively racy or violent shows have moved into the “family hour” of 8 to 9 p.m., and the sitcom, where a dimply kid phenom is most likely to sprout, is hurting, there’s less room for a precocious pre-teen to have any wholesome prime-time network appeal. Ray Romano used to joke in the opening-credit sequence of his dad-with-twins-and-a-daughter sitcom, “It’s not about the kids.” I guess the networks took him seriously.