In many cases, the certification process for therapy is such a time and money sink that people will become priests in small "religions" as a legal workaround to taking 1yr+ of archaic training.
How much depression, suicide and drug-abuse is caused by the desire to tightly control commercial human contact and the resultant dead-weight loss of people not getting enough of it?
Unless there is a pressing public health threat from an activity (e.g. someone who doesn't know how to drive, operating a motor vehicle on public roads), society should think very long and hard before restricting people from engaging in that activity.
If there is going to be licensing, it should be limited to restricting how people can market their skills, where only those licensed can market themselves as licensed. This gives quality-conscious consumers an easy way to identify licensed practitioners, while giving those who value affordability over safety the option of unlicensed services.