Rebuilds are difficult, they seem to stretch on forever and they are never fun for fans. The payoff can be worthwhile though, if front offices build their teams the right way. The Houston Astros famously made tanking a tactic, and they tanked to the top, winning the 2017 World Series. The Astros have remained one of the better teams ever since.
Even the big-spending New York Yankees aren't immune to down seasons and rebuilding periods. The Baby Bombers helped reignite the Yankees after a four-year span in which New York made the playoffs only once, losing the AL Wild Card Game to the Astros in 2015.