obviously there are levels of trust in every interaction yadda yadda... the important distinction is will the protocol be actually constrained by the on-chain supply or not?
credit networks with ecash mints will not be in any way constrained by what is going on on-chain. credit ecash spent via lightning is absolutely constrained by what exists on-chain.
Ark and other covenant pool constructs and rollups can not double pledge sats, every satoshi is expressed on-chain. and i know for a fact there is an easy magnitude of scaling there. with a level of trust (it's not completely trustless) but no perverse incentives and no capability to issue paper bitcoin IOUs.
trust is not inherently evil, but fall-back on settlment without trust and unilateral exit capability are necessary, not optional.