This isn’t really anything mind-blowing, but I find that one of the themes of Tengen Toppa Gurren-Lagann can be used to explain a certain aspect of the ending to Revolutionary Girl Utena in a rather straightforward fashion. As I’ll be discussing the ending to Utena, I think a spoiler warning is more than implied, but I’ll put one here anyway because I think both Utena and Gurren-Lagann have final conclusion that shouldn’t be experienced in the form of a paragraph. I advise you not to read this post unless you’ve seen both.
In the “epilogue” of Revolutionary Girl Utena, we see Ohtori Academy only nearly everyone has forgotten about Utena. At first, it seems like Utena ultimately had no impact on the students there despite everything that happened in the series, but little by little the show reveals subtle differences in the characters’ behavior, such as the fact that Wakaba now has a friend who looks up to her as much as Wakaba herself looked up to Utena. Then we see Anthy with Akio, where Akio is trying to revive the rose duels once more. Anthy, however, ends up walking away and (we presume) permanently out of Akio’s life.
If we look at Gurren-Lagann, the drill is one of the very overt themes of the series. The titular robot pulls them out of thin-air, the concept of the infinite power source that is “spiral energy” is derived from the same shape, and it appears in the show’s most famous quotes (“Your drill is the drill that will pierce the heavens!”). From that whole drill motif (though I can’t remember if it’s from a production interview or if it’s said in the actual show) comes the following idea: humanity is like a drill in that it moves forward with every revolution.
Now I believe that the Japanese word Gurren-Lagann uses for “revolution” is different from the one that Utena uses (回転 kaiten, revolving vs. 革命 kakumei, life-changing), but I think it explains the ending to Utena quite well. In the end, Utena did not defeat Akio, she did not permanently undo the rose duels, Ohtori Academy still stands, and Utena is gone from the world. However, it’s clear that she did indeed bring forth a revolution, and in that one revolution all of the characters were able to grow a little. All of the characters, that is, except for Akio. While Anthy is able to finally will herself to break free of the cycle that Akio has built up, Akio himself is shown to be a man who can no longer learn, who is doomed to repeat the mistakes of the past. Like the drill of the Gurren-Lagann, for the revolution that Tenjou Utena induces, (nearly) everyone moves one step forward.