That's only true if you choose for it to be. There are ways to formally prove that your software is correct but they require a large time tradeoff. For example, the software in the chip in your car has gone through as much engineering rigor as a bridge. Alternatively, look at a cheap toy produced in a shitty factory in an undeveloped country. It will have parts in it that were designed by a mechanical engineer but they choose to be less rigorous to keep cost savings low and as a result you get a toy with "bugs" in it.
We'd like to think so. I currently do some work for a static analysis company that has many, many customers in the automotive industry. The MISRA rules are part of the standard package bought by these customers, and an awful lot of MISRA violations will be caught by the analysis.
Then you get the example of Toyota, who I am pretty sure are one of the customers of my current employer (and some of their subcontractors/suppliers are also customers). They definitely had the opportunity to identify the failings in their software (some of which would definitely have been caught; recursion, for example) and either ignored the results, or just plain didn't bother.
And the civil engineers I used to work for had a bridge fall of its supports :-) I had to reverse engineer some software to help find the reason for that.
Those factors are "project management" which include concepts like "scope", "budget", and "critical path".
It's arguable if those are "engineering". They certainly affect engineering. (And likewise, some engineering constraints can feed back into project planning and feasibility.) In any case, project planning is a separate area of study. Using the author's strange definition of "engineering", it means the NASA Space Shuttle is "not really engineering" because it didn't deliver to the specifications of 50 launches per year at low cost.
A more reasonable definition of engineering that most could agree on would be, "the study (or art) of balancing technical tradeoffs against real-world constraints".