Agile is a thing already
Agile, as we know it, means any development framework or methodology that adheres to all or most of the values and principles listed in the Agile Manifesto, which was published in 2001. The Manifesto is the end result of several streams of exploration and experimentation that continued throughout the 90s (1990s, not 1890s). These streams resulted in the invention of eXtreme Programming, Scrum, Feature Driven Development, Crystal Clear, and other development paradigms. The genius of the Manifesto is that it captured in a very high level way the common philosophical foundations of these new approaches and dubbed those values and principles Agile.
In the 16 years since publication of the Manifesto, Scrum has become the Agile methodology of choice around the world, and also the software development methodology of choice around the world. The engineering practices associated with successful, high performance Agile software development have coalesced into the Devops movement, and in the modern world it seems incomplete to implement Agile without Devops, and vice versa. Additionally, user-centered design approaches have learned to take advantage of the feedback cycles built in to Scrum. Dozens of books and hundreds or thousands of blogs, articles, papers, and videos have been created on the subject of Agile, Scrum, DevOps and associated topics.
The plethora of material available on the subject of Agile software development leads one to wonder why so many organizations feel the need to re-invent Agile by creating their own homegrown dogma. They choose various subsets of Agile to preach, and sometimes to follow. We will default to using the discoveries and methods and knowledge of Agile in the existing worldwide community, only inventing our own when necessary.
Having said that, it’s important to note that it is assumed that basic Agile dogma such as the Scrum Process Framework requires supporting process and culture that arise from the local environment in order to work well. You could say that Agile is necessary but not sufficient in terms of creating the best product development approach for you.