Increased sales do not intrinsically require more engineers at most companies. It is possible for some companies to have required increasing engineering resources to cope with scale. But the vast majority of hiring was for people to work on future additional features to attract more customers. Zoom, Rec Room, DocuSign, and some other companies in that direct line of moving work and socializing online, yes. Facebook, Google, Salesforce, almost everyone? No.
Companies generally don't require more engineers, ever.
However, if there is demand for your product, engineers are a good way to make it better. If you don't make it better, that demand will go to a vendor who does.
Either way, if you believe these companies never needed the engineers in the first place, it is an entirely separate claim from the claims in this article.
And I'm not presenting some amazing new idea. People have been discussing for years that these companies hire people just to have them, not for business goals.
...and to clarify, you aren't addressing a claim that I made. You're making up an entirely different claim that is unrelated to my statement. You are contending that these companies don't know their operational needs and consequently hire and fire in arbitrary/capricious fashion. That may be, but it's irrelevant to the article or my point.
As you have pointed out, there has always been stories that large companies have unnecessary hires, and engage in strategies of cornering the market for labour. From that perspective, there has NEVER been demand for resources, there is no rationale for hiring more or fewer people, and nothing would constitute as "evidence" that there is demand.
Now the stuff you cite is not really supporting evidence of that. It's evidence that large companies often are inefficient and under-utilize use of their workforce. That is definitely not a new idea, and is well supported both by evidence and simply by intuition about the challenges of efficiently organizing people.
My claim was that given shifting labour demands, it's not necessarily "less harm" to under hire because at some unknown point in the future you may not want to have those hires.
Now, when you claimed that there was no evidence of an increase demand for labour... which really had nothing to do with my point. In part of my response to that claim that there no evidence with a statement that if there ever was evidence of demand, it was at that time.
There was, in fact, evidence. Maybe not sufficient to convince you, but certainly enough evidence to convince hiring managers. What there wasn't evidence of was that this increased demand would sustain itself forever. There never is. The idea that there is less harm in not hiring people because there is reason to believe that demand might decline at some unknown point in the future is just wrong. Sure, if you know that you only need someone for a week or a month, you shouldn't hire them for a long-term position. Not only is it harmful to them, but it is harmful to your organization. However, even if you know that need might dissipate at some unknown point in the future, if you know you need someone until something changes, there is no harm reduction in not hiring.
You can have dramatic gains in revenue, increased sales, increased subscribers, etc., and less 'available cash'. What you do have is more demand.