[ElConvoy]

Actually the only one that is happy with good toy sales alone is bandai.

Yes people take the ratings far too seriously some times but the thing is though when nobody would watch sentai why keep a show on the air nobody watches.
Keeping Sentai alive costs a ton of money for both toei and tv asahi so when the ratings drop so low that its not feasible for them to produce sentai anymore they will stop and it would pretty much become a toy only brand.

Ohranger had (and I think still has) the best toysales in sentai history and carranger also had pretty good toy sales. Still Toei and Asahi moved sentai to another timeslot because of bad ratings so they do matter. Sentai will probably not be cancelled as long as the series average is around the 3% mark and they would rather try another timeslot before they cancel the show completely.