Layers and accountants have specific post-graduate examinations. Doctors and dentists have an extended education combined with on-the-job training.
In the UK engineers can apply for chartered status, which assesses professional experience.
The reason software developers have none of these things is because the entry qualification for some jobs is "I know some javascript", while for others it's a post-graduate understanding of statistical distributions and vector calculus.
There's no professional accreditation system, no reliable way to assess professional competence, and a lot of the tools (and ideas, and systems) are hacked together with no formal rigour by people who like solving puzzles more than they like making things that work reliably.
