Iterative, incremental development - the core of agile - has been around at least since Barry Boehm described the "spiral model" of development in 1986, and has been successfully used for nigh upon 30 years since under various monickers (and I'll bet there were practitioners before Boehm's paper).
"Agile" has matured and developed a lot of inter-related supporting practices and tools that have made it increasingly powerful and easy to implement. Continuous integration, test-driven development, use of "stories" as a tool for requirements definition, you cannot tell me these techniques and tools are not successful.
I have personally seen the development practices of a company dramatically transformed for the better by having an agile trainer brought in and training the entire staff, including managers, and instituting formal agile practices. It is great when a junior developer can tell the VP of marketing to take a hike because his request has not been submitted through the grooming and priority assignment process.
This one experience gives me complete confidence that people mocking agile simply do not know what they are talking about.
One problem agile does have is with zealots who don't understand that this is, and has to be, a collection of related practices that must be tailored to the needs of the environment, not a one-size-fits-all, all-or-nothing thing. Another problem is thinking that "form" is what is important, not "what is happening".
For example: holding stand-ups is not agile. It is a common, useful tool to use in an agile environment. If your team is coordinating with informal sessions as needed, Skype, chat tools, and an updated Wiki in real time, and the managers are keeping in the loop using these tools, then maybe a stand-up is a waste of time for you. I think most teams benefit, but design and planning is not part of a stand-up, other meetings are needed for these.
There can be long-term planning that does not follow the agile model, and can be described as water-fall, and this has its place too. But I think the only really successful development practices are variants of an "agile" type process.