There's some poorly researched history of the manifesto and a LOT of straw-manning in this post. I'd encourage better research, starting with how Scrum is popular but not considered very agile.

Sure, if you already know exactly what the customers want, you can use waterfall and get that done. Let me know when that happens.

Until then, the difference between waterfall and the goal of agile methods isn't 2-week iterations. It's the speed of feedback and what is done with that feedback.

A company SHOULD have a long-term product strategy but strategy isn't implementation. Locking in a long-term implementation will impact strategy and usually in a negative way. They should adjust according to the feedback from early and often delivery.

I'd encourage you to read "Lean UX" and "Engineering the Digital Transformation"

Also, the manifesto is over 20 years old. You might try some material created in the last decade. "Continuous Delivery" is a good example as is "Accelerate."