Correction. My doubt now over few days on path-based redistribution was ungrounded.
Demurrage is single-hop. As I have pointed out before: Redistribution in Circles only over one hop? - Circles general - Circles Forum. It is a very important mechanism. But, path-based is network-to-node, rather than node-to-node. The latter reduces tax rate by network-size.
The coordination mechanism described was still inspired by demurrage. And should work. Technically though, the 3-phase I have described earlier, while it may be overkill, may also have benefits. The enforcement at each hop is much higher. In 3-phase, the delay fee only covers a combined attack vector between buyer and whoever causes delay (intermediary or seller). Thus my doubt on 3-phase may have been ungrounded too, but the simpler “finish-on-timeout+delay fee” 2-phase still seems to work, and it at least was inspired by considering for a few days if maybe demurrage was better…