The common person wasn’t aware of unconscious processes. Many still aren’t today. But even among health and academic fields back then, it was uncommon knowledge.
Did fiat make mental health worse? For sure. The devaluation of money is a huge stressor for everyone. But therapy is valuable regardless of what time we live in. I’ve seen someone who struggled with severe emotional and sexual abuse as a child, become extremely violent because of ptsd. He ended up in jail and got therapy after he was out. He’s a completely different person today. Manages anger and the ptsd well and has improved relationships with friends and family. There are people you will meet who seem very well rounded and healthy but have extremely dark pasts that they suffered to get over. And good therapists help these people get through that faster.
Even on a bitcoin standard, therapy will still have high demand because of these unconscious processes. And because humans aren’t perfect, parents with good intentions will unintentionally create psychological problems that their children will struggle with later on.