When you have so much of you career invested in something like Agile, XP etc... it can be hard to see the forest for the trees. I had a consulting job in The Haag many years ago. IBM was the incumbent contractor at the customer site (a bank) but after 5 years on the job they had not written a single line of functioning code. In the office there were two teams of software people... both behind closed doors. The first team was the Data team and the second team was Functional. They rarely spoke and they never shared information. I was there for a week, introduced the client to OO and we had a functioning prototype. Smart people do smart things, You cannot make an underachiever exceptional by using Agile. Either they get "it" or they don't.
I just commented on a blog. I'm sure there is some validity to his post beyond observing that Agile Scrum is broken. It certainly is not what it was originally intended but for that you have to go way back to Dave and Andy from PragProg. I have not found the original links and references myself but I recall enough from my reading at the time. Today's Agile does not look anything like what it was.
Scrum deflects from individual accountability. But the failure of agile/scrum is probably more psychology than technology. There are essentially three groups of people. 1) the high achievers that you want everyone to emulate; 2) the average devs; 3) and the low achievers. The high achievers hate these processes because it simply adds friction to their day. The low achievers love it because it deflects individual responsibility (think Survivor or Big Brother; the best do not always win. Floater is a legitimate strategy). And the average achiever is ambivalent and can be tipped either way.
Everyone is different and creative in their own way. You cannot herd cats with agile or scrum.
Agile does not treat people with respect. It dictates with strict rules what and how things are to be done. When the reality is that we have individual and collective responsibility. And most of that is encapsulated in an unwritten "bill of rights" that we carry around with us. At least the high achievers do. Translating that BOR to everyone else with a wide brush is simply too general an approach. Improvement from the under achievers comes from training, education, and more then anything else experience and experience from making mistakes.
The real chalenge here is that businesses are trying to grow their ranks as fast as they can. Many times that means hiring people that they would not hire if there was not such a shortage. This is a different set of problems from Agile and Scrum. This problem can be fixed by being selective, selecting people with aptitude for the work, selecting tools that lower the bar of entry, and managing people rather then allowing them to manage themselves.