I notice the article didn't mention anything about engineers, either. Licensing doesn't make sense in every industry, but when people's lives depend on someone doing their job right, I think it's fair to require that someone demonstrate a minimum level of skill.
Engineering is mostly critical because it is optimized for cost.
If cost wouldn't be such a major factor in construction then 'rule of thumb' and 'overkill' would be valid ways to get around having the knowledge to get an exact answer.
In olden times it was customary for the designer of an arch to stand under the arch when the construction scaffolding was removed. This quickly eliminated those that were not capable of constructing stuff that held up, even if it led to some constructions that were probably more solid than they had to be for their designed use.
On the other hand, that's why we can still marvel at some of this stuff today.
