as you divide larger categories into smaller and smaller subcategories, the probability that people assign to the total category goes up and up

The idea that when people disagree over complex topics that they should break their disagreement down is one I've learned in part from Robin Hanson and in fact he applies it cryonics

While Robin has fewer categories, if you look at the detailed probabilities that people gave we could throw out most of their answers without changing their final numbers; people were good about saying "that seems very unlikely" and giving near-zero probabilities. Most of the effect on the total comes from a few questions where people were saying "oh, that seems potentially serious". If I do this more I'll fold many of the less likely questions into more likely ones (mostly so I get a shorter survey) but I don't think that will change the outcome much.

I would expect unpacking to work for two reasons: to help avoid the planning fallacy and to let us see (and focus on) the individual steps people most disagree on.

unpacking all the disjunctive paths to success into finer and finer subcategories

As far as I can tell there's really only one path to success, and it's the one I put here. In my reply to torekp I talked about why I thought in-the-flesh revival was enough less likely not to matter. What would you put as disjunctive paths where "you sign up to get frozen and start playing for it" makes the difference is you being revived?

If any disjunctive paths are serious enough I'm willing to go back and add them to my model.

EDIT retracted: "looking up the Subadditivity effect I think your claim is just wrong. If anything breaking larger probabilities down makes for larger combined probabilities". [This was wrong because I was confusing the negative and positive formulations. Robin Hanson's is positive (which subadditivity should push in the 'cryonics-likely' direction) while mine was negative (which subadditivity should push in the 'cryonics-unlikely' direction).]