It's often a problem that gamers drift away from their favourite franchises as they get older and move on to higher education, careers, starting families, and so on. Reaching a younger audience is often difficult, which means many series are stuck with an aging fan base that shrinks with every new release.
Recently, for example, Square Enix warned of exactly this in the case of Final Fantasy, but Capcom, on the other hand, does not seem to have this problem. Everything they've touched for a long time has turned to gold, and it seems that with Street Fighter 6, they've achieved what others can only dream of.
In an interview with Game Spark, producer Shuhei Matsumoto was asked why there are so many brand-new fighters in the upcoming Year 4 season of Street Fighter 6. He revealed that over 70% of Street Fighter 6 players today are between the ages of 15 and 25 (translated with Copilot):
"First of all, the number of new users and young gamers has increased enormously in Street Fighter 6. Previously, people aged 35 to 40 made up the largest target audience, but in SF6, it's people aged 15 to 25 who dominate, and they actually make up more than 70 percent of the player base.
"Against this context, I get the feeling that the fact Street Fighter 6 has so many brand-new characters is truly appreciated."
In short, Street Fighter today has a fairly consistently young audience that doesn't have the same need to see old fighters return, which is perhaps not so surprising when a significant portion of the users weren't even born when Street Fighter IV premiered in 2008. However, that isn't the only reason; Matsumoto is also thinking about the future:
"As a brand, we also believe that increasing the number of new characters is good for Street Fighter's future history. From that perspective, we've created a roster this time that consists mainly of new characters."
All Year 4 characters are completely new in the sense that they have never been playable before. Arjun and Yasmine are both newly created, while Bosch appeared in World Tour as a rival (but was not playable). The fourth and final character is Final Fantasy VII icon Tifa, who is also making her Street Fighter debut.