Initially, the first half of Lost Galaxy was very successful. At the time, it had the highest ratings ever for a Power Rangers season. However, the ratings during the second half of the season went downhill a bit, not because the second half was bad, but because of some of the behind the scenes moves. The second half aired four months after the first half, which was common for PR seasons at the time. However, advertisement and promotion of the second half of Lost Galaxy was shunned by Saban in favor of promoting Digimon. Also, on set, Danny Slavin (Leo), had a fall out with the production crew and there was the contract dispute with Patricia Ja Lee (Cassie) who was set to replace Kendrix after Valarie Varone left the set due to having leukemia.
Power Rangers SPD also suffered a bit from executive meddling, regarding the Omega Ranger scenario. Disney didn't want an extra actor hanging around on set, so eventually the character Sam (the Omega Ranger) was written as a CGI ball of light whenever he was unmorphed due to time travel. This alienated many fans. Though strangely, Disney did nothing on RPM when there were even more actors on set than SPD.
Power Rangers RPM received an even worst treatment than Lost Galaxy did. Disney thought RPM was going to be the lame duck last season of Power Rangers, so they switched it from Toon Disney to ABC. RPM was also given terrible time slots, such as airing at 5am in some places and other places being subject to ABC's college football broadcast. In fact, in some cities RPM didn't even air. To top it off, promotion and advertisement was poor at best. As a result, RPM had the lowest ratings ever for a PR season, until MMPR v2 came out the next year.