alt Hacker NewsAgile, in practice, has turned into "disorganized waterfall." Witness absurdities like the existence of the "Agile Gantt Chart for Jira." The reason Waterfall, or modern Agile, are the way they are, is that they are systems that allows the smallest possible number of people to take responsibility, while allowing everyone to perform accountability. Basically nobody wants to lay it on the line and say to the CTO, "I'm going to make this project succeed." Much easier to say, "we're using best practices and modern processes."
This is a consequence of failing to train managers, especially in the moral dimension of management, which is entirely about accepting responsibility, and of promoting into management individuals who are not prepared to do so.
It turns out for large cross-team initiatives, organizing the work is as hard as doing it.
I like the example of internationalization. You need involvement from all parts of the product to release it - you rarely can sell a half-internationalized product. You need to work with external teams of translators who need to be fed the work in a consistent interface. There will be pieces of the work that nobody is going to forsee (e.g. pulling text from the database) that will be surfaced and handled consistently.
So, to get it out, you need to have each team prioritize the work. You effectively need a deadline, or the work will never happen. (The work is valuable for the company, but does not drive any individual team's customers.) You will have dependencies: Team A has to address part of the work before team B can. And you need a way for teams to report that they are done so that it can be reviewed for consistency across the product.
This is a bad fit for most agile methodologies, but you're not going to take everyone out of it temporarily and then go back in. So you have to accommodate a project within your system.
But these exceptions become more and more common as your company gets bigger and bigger. The only truth that I can find is that the only way to stay agile is to stay small: small teams naturally do the things that are agile.