Almost every new idea in software development is having problems when facing "majority adoption" phase. Agile definitely is replacing waterfall now and there are so many people that capitalize on this trend and don't give a shit about agile roots and principles. Every new wave is eventually hiped and monetized. Agile is not an exception. It doesn't mean agile is bad, it just means agile went mainstream with all side effects.

I personally have a strong feeling that this article is just another attempt to monetize agile, by selling "agile failure". Agile is not failed for sure. Some people did.