The reason Thunderbolts is the new Avengers is that in the Marvel Cinematic Universe (MCU) film "Thunderbolts*," the team known as Thunderbolts is officially rebranded as "The New Avengers" towards the end of the movie. This renaming is a strategic move within the story by the character Valentina Allegra de Fontaine, who publicly introduces the team as The New Avengers during a press conference, symbolizing a revitalized sense of unity and heroism different from previous Avengers lineups. The film and marketing deliberately use an asterisk in "Thunderbolts*" to hint at this transition and the dual identity of the team as both Thunderbolts and New Avengers. This change reflects a fresh narrative direction where the team, composed of unconventional and once morally gray characters, is stepping into a new heroic role in the MCU, paralleling some elements from Marvel comics but with a unique twist. The New Avengers lineup challenges traditional expectations and sets the stage for upcoming MCU events, including connections to the "Avengers: Doomsday" movie. Thus, Thunderbolts becomes the new Avengers by narrative design and marketing, indicating a new phase for the franchise's flagship superhero team.