Keeping websites on page one requires maintenance. Search engine rankings change every day, and periodic attention, even minimal attention, is necessary. The Downside Website management requires maintenance.
Successful websites attract repeat users by offering new material from time to time.
Search sites change the algorithms and methodology for ranking websites. That simple fact causes any given website's position to change, disappear, reappear, and generally confuse anyone trying to understand what is going on. Change is the nature of the environment we are working in. With regular monthly ranking monitoring, top pages which lose rank can be adjusted and reinstated. But, again, due to the lag time of search engine robots, it may take a month or more.