There are plenty of staff positions where incompetence could be very damaging or deadly to the business. E.g. in-house lawyers or accountants, even HR in some circumstances (failing to act in the presence of a hostile work environment). That doesn't mean it's not a staff position.
By the definitions of the article, the head of engineering at a tech company, or even the CEO, are considered support staff. Their success and failures will 100% map to the success and failures of the company.
The business school mantra is invest in profit centers, nickel-and-dime cost centers. If you are so unfortunate as to be at a company run by an MBA and are in a cost center, woe to you.
Some wise exec had the vision to outsource it to an external company and then Motorola (that was already on the path to its death) realized how much was done outside of the process (which is typical for such companies, fortunately or not).
Suddenly your threat of whatever happening if your thing is not fine had exactly zero value against "raise a ticket". Everything crawled to a stop because of that and "golden tickets" were used.
This is one true example of why you should think 20 times before outsourcing something you do not understand.
Why equate them as the same here?
The thing is that every non-tech company is now in some sense in the tech industry, whether they mean to be or not; a large part of their business is done online. As opposed to companies that specialize in building tech for other companies, many of them have nickel-and-dimed their way into their own hardware/software infrastructure and the maintenance of that has become crucial to their normal operations, to the point where instead of business logic dictating changes to it, it frequently dictates changes to their business logic. That puts independent devs for those companies in a kind of catbird seat to determine which stacks and which infrastructure are going to drive the next round of growth. Some people (like my friend who's a salesman for Salesforce) call this "technical debt", but really it's bootstrapping and the better and cheaper you can do it through indy devs, the better your bottom line.
So it's quite different than the normal software world, but it's neither what you're calling a staff position nor is it actually a line position.