How markets in the poorest of countries revolve around circular markets working on about $1/day. How can these people use bitcoin non custodially when each transaction they make on chain would cost them 1/5 of their daily income? If fees ever go above 1 sat/vbyte, I would find it very hard to convince any of these people to use bitcoin. Every solution I can think of involves at least one on chain transaction or custodial solutions.