Crypto is all about decentralized proof of trust yet somehow this eludes people who should know better. Please show me how you solve decentralized proof of trust (double spend) with postgres.

Indeed, crime did have a need for anonymous proof of trust that crypto solved. Why did crime have a need for that? Because crime lies beyond the realm of the status quo.

Criminals are to the status quo as pioneers and revolutionaries are.

In the "normal world", centralization gives us the situation where the organization in charge of authentication is the same organization that has the monopoly on violence. Indeed within the rules of this story we built crypto seems to be "a solution looking for a problem", as another stereotype argument goes. The problem is all around you.