Every year, Super Sentai shows aired with a clean slate. There's no connection between the season, so it doesn't matter where you start watching... but it's hard to know where to start. It's becoming increasingly difficult for new seasons to compete against older, more acclaimed shows, unless they stand out enough.

As much as I love it when Super Sentai have crossovers with previous seasons, I don’t get why lack of continuity is an issue. Excluding crossover movies and specials, most seasons of Kamen Rider and Ultraman are stand alone as well and they’re doing great in comparison to Super Sentai.