Trust is what we see
Or what he feel.
Or don't see if there is none. But "trust, support, and confidence" cannot be based on nothing, since there is always something (reality or delusion as in the case of tulipomania) which they should rely on and stem from.
Getting a bit phycological here ? We're drifting away from the technical discussions though.
With Bitcoin, it is the blockchain technology and its decentralized nature which are the basis for these things. With fiat, it is the power and might of the state behind this fiat. If this power is wasted (like it happened in the Roman Empire), it won't take long for the government money to lose its value as well as trust along, with that
It is 2017,people have already fallen victims to government's policies.They wouldn't miss a chance to revolt against the government ways of controlling their power/money (both are the same either way).Fiat is really dead long time back when credit/debit cards replaced the traditional exchange method.It's a matter of days until the remaining disappears too.