I think a lot of useful lessons (that will actually stick) have come out of this extreme pendulum swing, though. Many have realized that waterfall is just a death-march but, they have also realized there is no Agile Faerie Dust, either. Plus, there is not one methodology to rule them all.
Agile principles certainly have an ongoing role to play but, there is no single recipe. Realizing that may be the biggest benefit of all.
(This is a photo I took of a sunset at Bellingham Bay, several years ago.)