Many of today’s big shōnen series feature a point where the plot is suspended for a given period of time, otherwise known as the time-skip. A lucky few witnessed it in Dragon Ball the way Akira Toriyama meant for it to happen; Goku grows up over the course of the series. Why has this become such a popular narrative device?
Many of the series which employ a time-skip feature characters which have powers which progress over the course of a long series. One Piece, Dragon Ball, and Naruto eventually reach a point where the main characters simply don’t have enough power to defeat their foes, and the time it would take to train them to an adequate level would bore the viewers. Given the variety of characters that enter the series by the point of the time skip, it can be used to even the playing field to make the series more believable as well.
The length of these anime also mean that an invested viewer will be watching/reading about these characters for a long time. For example, I learned about One Piece in the fourth/fifth grade, when Usopp’s introduction to the series was news. That was about 19 years ago, and the series still has plenty of life in it. The time-skip, if used correctly, can add a level of depth to the characters by giving them the illusion that they’re aging. For a series such as Lupin III, few people are interested in how lifelike the characters are because they’re more invested in the random adventures they have. Along with the main characters, the entire series can receive a figurative breath of fresh air, while retaining all of the elements which make it memorable. When Naruto Shippuden was being translated into English, some of the main questions in my mind was “What’s changed? Who’s changed positions in Konoha? What have the villains accomplished in the time that’s passed?” The new series was almost like learning about Naruto for the first time.
Personally, I like time-skips, though they’re bordering on becoming a cliché in the anime/manga industry. Almost everyone in the shōnen genre has done it, but many of the mangaka who have done so have been successful. I wish the industry would focus on adding new and innovative elements to make stories interesting, but that’s a post for another day.