Agile thinking has been around for quite awhile. And you are absolutely right that "good projects are delivered through good project management." That is no different for an Agile approach. Agile has key principles that must be utilized in order for the approach to work.
Saying that "We'll do Agile for everything BUT..." is like saying I'll do the traditional waterfall method and gather requirements BUT I'm not going to do a design document or I'm not going to put milestones in my project. You get the idea. That thinking doesn't work for waterfall and it won't work for Agile either.
If you are willing to embrace the approach then it can be a good tool in your toolbox. The article points out that it isn't your only tool and some projects might not be as well suited to an Agile approach. So, again your right it is not a "silver bullet" or "one ring to rule them all".
Lastly, when you have folks that are used to doing things in a particular "waterfall" way it can be hard to switch paradigms. You can't just wake up one day and say that we are going to do Agile from this point forward and we are going to do it flawlessly. It took the trust's IT department 18 months to get up to speed on this approach. It helps if you can find an industry expert or an outside firm to provide some support or training while you take on this new process.
Agile does work. There is plenty of evidence to show that it is a viable and sustainable approach.
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