I'm coming back around to this because your remark about PF2 being a "shameless treadmill" stuck with me. You seem to be talking not about Pathfinder 2: the game system but rather the pre-written adventures that are offered with it. I could see modules being too narrowly tailored to offer only challenges that are consistently neither too easy nor too hard. While my GM has told us he'll use a published Adventure Path (I'm not sure of the name and don't care) it wouldn't be my style as a GM to do so. The last time I ran a canned adventure was in 1995 or '96, and it was at the request of the gaming group. My adventures I design purposefully with a range of encounter difficulties.