According to the Stack Overflow's 2016 Developer Survey [1], "56% of developers in fact do not have a college degree in computer science or related fields"

Admittedly, the data is a few years old (and I didn't want to pull the same data from the 2018 survey), but such a requirement would put many people out of a job. I also haven't seen any concrete data that would support any correlation between the efficacy of a software engineer and whether they had obtained a college degree, so this seems like a poor metric.

I share your incredulity regarding the lack of any sort of "occupational license" for the industry, though I remain unconvinced that instituting one would have a positive effect.

[1] : https://stackoverflow.blog/2016/10/07/do-developers-need-col...