Agile is all about fail fast. An agile team will be able to respond to a customer's requirement quickly without involving any circus from the development team. It doesn't really matter much which agile framework the team is using: Scrum, Kanban, XP, or something else. What really matters is, are you following them seriously?
As an independent software consultant, I have personally observed and learned who generally complains, and why they complain about agile.
As Scrum is one of the most popular agile frameworks, let's assume a product company, say, ABC Tech Private Ltd., has decided to follow Scrum for the new product that they are planning to develop. The good news is that ABC Tech, just like most organizations, also hosts a Sprint planning meeting, a daily stand-up meeting, Sprint review, Sprint retrospective, and all other Scrum ceremonies efficiently. Assume that ABC Tech has ensured their Scrum master is Scrum-certified and the product manager is a Scrum-certified product owner. Great! Everything sounds good so far.
Let's say the ABC Tech product team doesn't use TDD, BDD, ATDD, and DevOps. Do you think the ABC Tech product team is agile? Certainly not. As a matter of fact, the development team will be highly stressed with a hectic and impractical schedule. At the end of the day, there will be very high attrition, as the team will not be happy. Hence, customers will not be happy, as the quality of the product will suffer terribly.
What do you think has gone wrong with the ABC Tech product team?
Scrum has two sets of processes, namely the project management process, which is covered by Scrum ceremonies. Then, there is the engineering side of the process, which most organizations don't pay much attention to. This is evident from the interest or awareness of Certified SCRUM Developer (CSD) certification in the IT industry. The amount of interest the IT industry shows to CSM, CSPO, or CSP is hardly shown to CSD, which is required for developers. However, I don't believe certification alone could make someone a subject-matter expert; it only shows the seriousness the person or the organization shows in embracing an agile framework and delivering quality products to their customers.
Unless the code is kept clean, how is it possible for the development team to respond to customers' requirements quickly? In other words, unless the engineers in the development team embrace TDD, BDD, ATDD, continuous integration, and DevOps in the product development, no team will be able to succeed in Scrum or, for that matter, with any other agile framework.
The bottom line is that unless your organization takes the engineering Scrum process and project management Scrum process equally serious, no development team can claim to succeed in agile.