80% of all machine learning engineers work at Google or Facebook
medium.com
medium.com
Also the blog/submission title is clickbait and likely an outright lie. From the original article/thoughtpiece (https://www.forbes.com/sites/groupthink/2018/02/09/tradition...) you cite as a source, emphasis mine.
> For example, fully 80 percent of machine learning engineers with Ph.D.s. are scooped up by Google and Facebook, especially those that have patents.
This makes testing even more important than usual, but testing ML systems is even harder than testing normal software, so you're in a shitty place either way.
ML ends up being this sort of bimodal level of difficulty, either it's super easy and everything works without much effort (it happens sometimes), or it doesn't work quite how well you need it to and you should probably be ready to sinks many months into it.