What does it mean exactly when Wikipedia calls Annihilationism a legitimate minority opinion within modern conservative Protestantism?

The [Wikipedia article](https://en.wikipedia.org/wiki/Annihilationism#1900s_onwards) regarding Annihilationism states: "Annihilationism seems to be gaining as a legitimate minority opinion within modern, conservative Protestant theology since the 1960s, and particularly since the 1980s." This sentence condenses a lot of information. What does it mean exactly? How small or big is this minority? Does it look different in progressive theologies (whatever that would be)?