I don't think it's all that radical.
Jeffro and his faction have a bit of a novel spin on faction play and high level campaigning, but the "Begin by clearing your mind of the last 40+ years of bad advice. Stop thinking of RPGs as a storytelling process. Stop thinking of each session of play as a single episode in a larger story" stuff is not novel. People in the OSR have been talking about much of this stuff for more than twenty years. Heck, the original West Marches campaign which made sandbox player-driven play as famous as it has been for the last several years ran from 2001-2003 in 3rd ed, and Ben Robbins' blog posts about it were in 2007. Jeffro didn't come out advocating for his play style until what, 2020?