All their standardised templates and processes mean that the Accenture 'experience' for clients is consistent but it does seem to reduce the capacity for creativity and flexibility in approach.
Their business works because they realise the world is big, so they focus on sales. They are amazing at selling their rubbish to anyone and everyone and know how to rack up billable hours. If a project succeeds (prob because it's easy), then great! If it fails, then move on to the next victim.
Also, the truth is that a vast number of very senior people are non-technical, which is why they get taken in by the machine-learning/AI/blockchain BS the consultancies have been spouting for the last few years. Once they get their foot in the door, they'll convince many a CEO to purchase their magic beans.
Generally on projects I’ve been on with Accenture involved they use their size to push through what they want and how they want to do things regardless of everyone else. One thing they do well is talking to the stakeholders, it’s all sales at the end of the day.