[Suzu]

Actually, this development is only natural looking at Japan's demographic as well. Japan has an extremely low fertility rate these last years, so there are less children and it's pretty obvious that less children also means less people who watch children's TV shows (I think the ratings for Kamen Rider also dropped, but not as much). Broadcasting a show at 7:30 in the mornig automatically gets you a much younger audience, because most older fans tend to sleep longer- also, these days, it's fairly easy to watch the shows online or get the DVDs, so basically, you don't even have to watch the broadcast live.
The toy sales, however, were fairly good with Kyoryuger, which means Toei will want to keep the show- if the ratings keep on dropping, Asahi might have to consider a new slot to broadcast the show. It could be moved back to evenings, like in the 90s, when families watch together- might be worth a try.