So many people left their wealth in the system only to watch it get eroded and utterly destroyed over time. The reasons were many: patriotism, inertia, disbelief, and denial cruelly fed by hope every time prices moderated or even retreated momentarily.
The simple observation is that many people had a blind belief in the money system. They lost their wealth because they were unable or unwilling to allow reality to challenge their beliefs. It's not that there weren't numerous warning signs to heed -- in fact, they could be seen everywhere -- but most willfully ignored them.