If you can pay for a single fully trusted node to do the calculation once, the cost of n nodes redundantly calculating the same result in order to establish trust must require those untrusted nodes to be cumulatively cheaper than the one trusted node, in order for there to be an economic incentive to do so, no?

My assumption is that you would have to be faithful in a low number of untrusted nodes in order for that to end up cheaper.

The cases of folding and SETI are particularly different because there are institutions which have in interest in funding these programs in part due to their goal being a public cause. The same clearly doesn’t apply to micro tasks if you will.

But I can imagine cases in which you can accept bad actors giving bunk results for some percentage of the calculations you run. As long as you’re rotating nodes often enough (provided that they’re from distinct actors) I’m imagine it could work out to be economically more feasible to spend the time to work around that bad data than it would be to directly hire fully trustable compute power.