Licensing and the perceived rigor it signifies is irrelevant to whether something can be considered "professional engineering." Engineering exists at the intersection of applied science, business and economics. So most software projects can be YOLO'd simply because the economics permit it, but there are others where the high costs necessitate more rigor.

For instance, software in safety-critical systems is highly rigorously developed. However that level of investment does not make sense for run-of-the-mill internal LOB CRUD apps which constitute the vast majority of the dark matter of the software universe.

Software engineering is also nothing special when it comes to various failure modes, because you'll find similar examples in other engineering disciplines.

I commented about this at length a few days ago: https://news.ycombinator.com/item?id=45849304