Scrum is the new waterfall

You cannot fit the same tire on a truck and a kid's tricycle, same way you cannot fit the same process for all development cycle. If you team needs clear direction and everything well defined (written in stone), follow waterfall. If your team needs formal process but can do some things on their own (say a team filled with new hires and one lone experienced dev), scrum might not be so bad. Kanbaan is good when everyone knows what they're doing and you really just want to know which stages do you need to focus more on.

You're best bet is probably to try all three and whatever else exists, mix and match until you can successfully deliver your products without a whole lotta overhead and then keep tweaking the process when conditions change (new hires, folks leaving, change in goals/features).

And how, if you are working on software for ESA, or working for one of the largest internet retailers, or if you’re writing a control software for railway switches, waterfall is the only possible option.

Even if the target is moving, agile is never able to provide quality.

Some of my professors were hired before by large internet retailers to spend weeks trying to understand even their business processes, as the retailer had built their infrastructure without oversight and every employee was working on whatever they wanted.

Just this "trying to understand what even is going on" helped them improve their processes and greatly increase their profit margin, as they were able to make many things more efficient with rethinking and rewriting.

EDIT: I’ll add my definition of quality here: Your software is able to interact with third parties without them ever having to rewrite their software, your software can run for decades without or with little maintenance, and your software is well documented. In my opinion, Agile is very ill suited for these requirements. One example is the Internet of Things, where you can be sure no one is ever going to update their smart washing machine

Nothing in the article makes me trust this persons perspective over any other. It's not thoroughly investigated with metrics over many case studies. There's no empirical evidence to back up his assertions. He doesn't have a reputation for other work that would make me trust his informed opinion over any others.

There seems to be hundreds of articles touting every possible side of this issue, why did this one strike a chord?

It's totally okay not to be great, but when you're not great you need help, and help comes in the form of management, and management needs a way to set and manage expectations. Agile is one way, waterfall is another.