My key complaint about Agile (or agile) isn't the concept or the execution -- it's where people choose to apply it. They think it works everywhere, all the time. But it doesn't. Agile works only for the right customer, on the right project (size, complexity, value delivery requirements, etc.), with the right team... there are a lot of considerations.

To me, agile makes the most sense as a software development organizing principle when the software being developed is a more or less "living" system, where it's large enough that you can work on pieces of it at a time and release updates along the way in a CI/CD model, and your customers / stakeholders are ready to accept that continuous / incremental delivery model.

That's a lot of dependencies. And not every project / customer / problem to solve fits in that mold.